1. doi> RAL, 16 Feb 2005 Norman Paskin, International DOI Foundation Digital Object Identifiers for Science Data

2. doi> Outline What is a DOI Persistent identification and resolution Functional components Example applications in science data (2) Open Q&A Slides are available electronically –some slides are hidden (run in presentation view) –sequence of builds 29 - 49 References are in penultimate slide –See especially CODATA 2004 article Print handout of Internet Registries article Possible other topics for discussion: semantic interoperability (data integration)

3. doi> Digital Object Identifier = DOI A name (not a location) for an entity on digital networks AND/OR A system for persistent and actionable identification and interoperable exchange of managed information on digital networks –Standards-based components Developed as cross-industry, cross-sector, not-for-profit effort managed by an open membership collaborative development body –International DOI Foundation (IDF) In widespread use now: –Over 15 million assigned, over 1000 naming authorities (users) –Key feature of scientific primary publishing as part of CrossRef system –Adopted for government documents (EC, OECD, UK, etc) In use, is a mechanism “behind the scenes”, –e.g. looks like a URL in a web context One application is interoperable common system for identification of science data: two projects considered as examples: –TIB project (citation of primary data sets) –Names for Life (biological taxonomy)

4. Identification and resolution Identifier: A unique label for an entity involved in a transaction Note the ambiguity of “identifier”: –Label alone (e.g. ISBN) –Specification alone (e.g. URN) –Implemented specification (e.g. DOI, Bar code) Ideally, persistent Ideally, actionable … Resolution: The process in which an identifier is the input (a request) to a network service to receive in return a specific output Both concepts are in principle neutral as to technology implementation Abstract concepts, but implementations typically at least “internet” TCP/IP (the more general the better, e.g. not just “Web”)

5. Persistence "It is intended that the lifetime of a [persistent identifier] be permanent. That is, the [persistent identifier] will be globally unique forever, and may well be used as a reference to a resource well beyond the lifetime of the resource it identifies or of any naming authority involved in the assignment of its name.“ [Persistent Identifier] = URN in IETF RFC 1737: Functional Requirements for Uniform Resource Names. (http://www.ietf.org/rfc/rfc1737.txt) Technical and social infrastucture issues

6. Interoperability Persistence is one dimension of interoperability: –“persistence is interoperability with the future” We know what we mean, but others may not. –Identifiers assigned in one context may be encountered, and may be re-used, in another place (or time) - without consulting the assigner. You can’t assume that your assumptions will be known to someone else. Interoperability = the possibility of use in services outside the direct control of the issuing assigner Identifiers may be opaque or may be meaningful – but meaning only makes sense in context –Normally, opaque string is the safest assumption –User communities define rules (social infrastructure; namespaces) –Interoperability guarantees others can interpret even if they do not know rules NB: The recent chemistry identifier proposal INChI is an interesting meaningful identifier

7. 1. Obvious: Assign ID to resource Once assigned the number must identify the same resource –Beyond the lifetime of the resource, or the assigner Two principles for persistent identification resource ID 2.Less obvious: Assign Resource to ID The resource must be “identified” –Must ensure it is always the same thing (bound) –Describe the resource “content” [with precision] –Failure to do this will ultimately break interoperability How far do we go in each? Depends on what we think is “good enough” – Technologists have focussed on (1) [and “bags of bits/data structures”]. – The content/rights world (2) [and focus on “intellectual content”] – Both viewpoints valid – (2) is now becoming more relevant

8. Resolution: The process in which an identifier is the input (a request) to a network service to receive in return a specific output “Point and click” is what I do (URL model), so: “what I point to (resolve to and get) is what is identified”, right? No –Point and click “get” is not referencing –Can identify but not “get” directly things that are intangible (works), or fugitive (performances) or that change: (“Todays NY Times”) or people and concepts…. –Pointing and clicking can return different things in different contexts, or give multiple options Identifier identifies an entity. Pointing and clicking is a service about that entity Entities can be physical, abstract, tangible, intangible, things, people, concepts, instances, … Resolution provides a mechanism to describe the resource “content” through a service which delivers a description Resolution and “What are we identifying?”

9. Document on screen Abstract work? Manifestation of abstract work? Version? This HTML file? All/some of these? What are we identifying?

10. 1994: Functional Requirements for Uniform Resource Names N  L

11. 1995: Persistent URLs – redirection service L  L

12. 1988-95: DO architecture, Handles N  L Wider scope than “the web”: the internet

13. Persistent identifiers on the web: observations The 'web' has moved beyond html: anything that moves data using http and “identifies” information entities using URLs. URLs, as currently understood, are demonstrably not persistent –calling them URIs doesn’t fix that The IETF RFC consensus process, and the separate existence of W3C, leads to ongoing debate and standards with a vague existence –compare with ISO standards –W3C web site on naming and addressing is “incomplete” –Current discussion of “non-IETF” namespaces as separate (info, DOI) The Web is not the universe –It is not all of digital information (<1%): see “How much Information” [e.g. email; Blackberry services medical, legal] –It is not all of the internet (see “What is the Internet..”) URI is a useful catch-all syntactic device for referencing in XML – can describe e.g. ISBNs as URIs –It is useful to have such a single framework which can accommodate any other identifier for referencing –But it is not, as such, persistent (nor predictable)

14. Information Identification - a report to STM publishers (Mar 95) Uniform File Identifiers - a report to AAP publishers (Oct 95) “..need to unify in one scheme music, audiovisual, document management, internet engineering, digital libraries, copyright registration and object based software” [i.e. web was not the focus] “..maximise utility of digital objects; enable core interoperability; enable integration of disparate sourced data; ability to trace ownership to manage rights” requirements: –protect legacy investments –enable interoperability –provide link between digital and physical –maintain privacy of users –have persistence –standard syntax –global scalability –global uniqueness –global meaning Led to launch of DOI initiative (AAP committee, Uniform File Identifier) 1995: Armati Report

15. Identification and resolution Resolvable identifiers must specify: –Agreed numbering syntax –Resolution mechanism –Data model to define “what it is we are identifying” –Technical and social infrastructure to implement (compare physical world bar codes) These could be assembled ad hoc, or offered as a packaged system (e.g.DOI)

16. Issues for persistent identifier applications What are we identifying with this identifier? [content not just bits] What are we resolving to from this identifier? What, if any, explicit metadata are we making available? How will the cost of providing the infrastructure be met ? The mechanisms must allow: Identification of entities of all forms –To be used in variety of contexts Appropriate use of metadata at appropriate level –Development of ontology tools to describe entity relationships Identification  Persistent  Interoperable  Automation  Precision  Logic

17. Data Model Internet Resolution Numbering scheme Policies DOI is the combination of these four components doi>

18. DOI syntax can include any existing identifier “label” formal or informal, of any entity An identifier “container” e.g. –10.1234/NP5678 –10.5678/ISBN-0-7645-4889-4 –10.2224/2004-10-ISO-DOI NISO Z39.84, DOI Syntax

19. Internet resolution allows a DOI to link to any & multiple pieces of current data Resolve from DOI to data –initially to location (URL) – persistence May be to multiple data: –Multiple locations –Metadata –Services –Extensible user-defined Uses the Handle system -Implementing URI/URN concept -Running on TCP/IP (common co-inventor) -IETF RFCs 3650, 3651, 3652 -To be in GRID Globus tool kit -Full Unicode compliance

20. Data Dictionary + DOI AP framework DOI Data Model = Metadata tools: –a data dictionary to define + –a grouping mechanism to relate Necessary for interoperability –“Enabling information that originates in one context to be used in another in ways that are as highly automated as possible”. Able to use existing metadata –Mapped using a standard dictionary –Can describe any entity at any level of granularity –indecsDD which incorporates ISO MPEG 21 RDD IDF is the MPEG21 RDD registration authority

21. DOI policies allow any model for practical implementations Implementation through IDF –Governance and agreed scope, policy, “rules of the road” –Technical infrastructure: resolution mechanism, proxy servers, mirrors, back-up, central dictionary, –Social infrastructure: persistence commitments, fall-back procedures, cost-recovery (self-sustaining), shared use of system –Not a standard but a Registration Authority/maintenance agency IDF delegates through Registration Agencies –Each can develop own applications –Use in “own brand” ways appropriate for their community (eg: CrossRef)

22. DOI to become ISO TC46/SC9 standard Home of “identification numbering”: identifiers for semantically meaningful entities: ISO 2108 International Standard Book Numbering (ISBN) ISO 3297 International Standard Serial Number (ISSN) ISO 3901 International Standard Recording Code (ISRC) ISO 10444 International Standard Technical Report Number (ISRN) ISO 10957 International Standard Music Number (ISMN) ISO 15706 International Standard Audiovisual Number (ISAN) ISO 15707 International Standard Musical Work Code (ISWC) ISO Project 20925 Version identifier for Audiovisual Works (V-ISAN) ISO Project 21047 International Standard Text Code (ISTC) http://www.collectionscanada.ca/iso/tc46sc9/index.htm Information and Documentation - Identification and Description

23. doi> Resolve The Handle resolution technology allows you to access any kind of Service associated with your DOI. eg Services can include metadata services Identify DOI syntax can include any existing identifier, formal or informal, of any entity eg 10.2341/0-7645-4889-1 10.5678/978-0-7645-4889-4 10.1000/ISBN 0764548891 10.1234/Norman_presentation 10.2224/2004-10-28-ISO-DOI Describe DOI metadata can be of any type, standard or proprietary eg OnixForBooks OnixForSerials IEEE/LOM MARC Dublin Core Proprietary scheme DOI combination of components A package of services is an Application Profile (to interoperate with anyone else in the DOI network, map to the Data Dictionary (iDD)

24. doi> DOI and scientific data DOI is already the core technology for maintaining cross-reference –persistent links between a citation and internet access to article CrossRef system used by 350+ publishers representing bulk of STM articles (as pre-publication link builder) both for profit and not for profit, OA, www.crossref.org 9,000 DOIs per day added to CrossRef. –Over 12 million DOIs now registered with CrossRef, –Over 850,000 assigned to books and conference proceedings. Several projects suggested to IDF using DOIs for data (not connected with CrossRef) –physico-chemical property data; biological microscopy images. –See Paskin, ICSTI 2002 paper Some sectors have developed their own identifiers, –e.g. Life Science Identifier (I3C/IBM): simple URN mechanism, non- generic, non-global – but very useful in bio-informatics –These can be incorporated into a DOI if needed to make globally interoperable and extensible Two projects in particular have developed DOI applications:

25. doi> (1) TIB: Citation of Primary Data Problem: re-use of existing data sets –Attribution of data source: make data publications citable in a standard way (cf. articles Citation Index) –Archiving of data in context so as to be discoverable and interoperable (usable by others) Background –CODATA National Committee WG, grant-aided by DFG (Sept 2001 to May 2002): Report "Concept of Citing Scientific Primary Data“ –Continuation as project for pilot implementation funded by DFG Oct 2003 to Oct 2005 at TIB (German National Library of Science & Technology) –Development of DOI registration agency for Data Solution: -DOIs for data sets, with associated metadata -Core management metadata applicable to all datasets -Structured metadata extensible to specific science disciplines -Follows principles of DOI Data Model

26. doi> (1) Citation of Primary Data: illustration of solution During her research for the World Data Center Climate (WDCC) Dr. Weather gains primary data about the weather in Hannover in the year 2003. –Primary data is tested, evaluated, stored and administrated at the WDCC. –Primary data is registered and allocated DOI at the TIB –With quality control of metadata, no change once allocated, etc Dr Weather can now cite this with a resolvable DOI e.g DOI:10.1594 /WDCC/W_Han_2003_MMB_2 10.1594 (Prefix) = TIB as the registration agency. WDCC = research institute. W_Han_2003_MMB_2 = internal name of the Data DOI is resolvable directly, or via http as http://dx.doi.org/10.1594/WDCC/W_Han_2003_MMB_2

27. doi> (1) Citation of Primary Data: illustration of solution Usage scenario 1: attribution of source Dr. Storm is reading publications from Dr. Weather in a journal and would like to analyse her data under different aspects. Can resolve the DOI to obtain the data set for use In his publication ”Comparison of the weather from Hannover and Miami” Dr. Storm cites Dr. Weather’s data using its DOI, referring to the uniqueness and own identity of the original data. Citation example: Weather, 2003: “Weather in Hannover for 2003” doi: 10.1594/WDCC/W_Han_2003_MMB_2 Usage scenario 2: archiving for re-use Mr. Nice is writing a paper about the sales figures of ice cream in Hannover in 2003, but he has no information about the weather. Searches via TIB central registration agency metadata search Result is doi:10.1594/WDCC/W_Han_2003_MMB_2 He resolves the DOI to find the data. The metadata refers him to the WDCC as publisher and data archive. In his paper he cites the data using the DOI.

28. doi> (2) Names for life: Biological taxonomy Problem: “Future-proofing biological nomenclature” –See Garrity and Lyons, OMICS, 2003 For a given nomenclature in a biological taxonomy, change occurs –e.g. new species recognised, species reassigned as the founding species of new genera; synonyms; species split into subspecies which later became separate species; –resulting in changes of names, genera, families, classes, relationships over time –How does researcher keep track? Solution: DOI proposed as tool –a data model of nomenclature and taxonomy –enabling disambiguation of synonyms and competing taxonomies –a metadata resolution service –enabling dissemination of archived and updated information objects through persistent links

29. nomenclature (2) Names for Life: illustration of problem doi>

30. macleodii (T) communis Alteromonas 1972 vaga nomenclature

31. communis vaga haloplanktis Alteromonas macleodii (T) 1972 1973 nomenclature

32. communis vaga haloplanktis rubra Alteromonas 1972 1973 1976 macleodii (T) nomenclature

33. communis vaga haloplanktis rubra citrea Alteromonas 1972 1973 1976 1977 macleodii (T) nomenclature

34. communis vaga haloplanktis rubra citrea esperjiana undina Alteromonas 1972 1973 1976 1977 1978 macleodii (T) nomenclature

35. communis vaga haloplanktis rubra citrea esperjiana undina aurantia Alteromonas 1972 1973 1976 1977 1978 1979 macleodii (T) nomenclature

36. communis vaga haloplanktis rubra citrea esperjiana undina aurantia putrifaciens hanedai Alteromonas 1972 1973 1976 1977 1978 1979 1981 macleodii (T) nomenclature

37. communis vaga haloplanktis rubra citrea esperjiana undina aurantia putrifaciens hanedai luteoviolaceae Alteromonas 1972 1973 1976 1977 1978 1979 1981 1982 macleodii (T) nomenclature

38. communis vaga haloplanktis rubra citrea esperjiana undina aurantia putrifaciens hanedai luteoviolaceae vaga communis (T) MarinomonasAlteromonas commune vagum 1972 1973 1976 1977 1978 1979 1981 1982 1984 multiglobiferum japonicum minutium biejerinckii maris hiroshimense pelagicum pusillum jannaschii kreigii Oceanosprillum maris williamsae linum (T) macleodii (T) nomenclature

39. communis vaga haloplanktis rubra citrea esperjiana undina aurantia putrifaciens hanedai vagabenthica hanedai MarinomonasAlteromonas putrifaciens (T) Shewanella japonicum minutium biejerinckii maris hiroshimense multiglobiferum pelagicum pusillum commune jannaschii kreigii vagum Oceanosprillum maris williamsae 1972 1973 1976 1977 1978 1979 1981 1982 1984 1986 luteoviolaceae communis (T) linum (T) macleodii (T) nomenclature

40. 1972 1973 1976 1977 1978 1979 1981 1982 1984 1986 1987 communis vaga haloplanktis rubra citrea esperjiana undina aurantia hanedai luteoviolaceae denitrificans vagabenthica hanedai MarinomonasAlteromonasShewanella japonicum minutium biejerinckii maris hiroshimense multiglobiferum pelagicum pusillum commune jannaschii kreigii vagum Oceanosprillum maris williamsae putrifaciens putrifaciens (T) communis (T) linum (T) macleodii (T) nomenclature

41. communis vaga haloplanktis rubra citrea esperjiana undina aurantia putrifaciens hanedai luteoviolaceae denitrificans vagabenthica hanedai MarinomonasAlteromonasShewanella japonicum minutium biejerinckii maris hiroshimense multiglobiferum pelagicum pusillum commune jannaschii kreigii vagum Oceanosprillum maris williamsae 1972 1973 1976 1977 1978 1979 1981 1982 1984 1986 1987 1988 colwelliana putrifaciens (T) communis (T) linum (T) macleodii (T) nomenclature

42. vagabenthica hanedai MarinomonasShewanella japonicum minutium biejerinckii maris hiroshimense multiglobiferum pelagicum pusillum commune jannaschii kreigii vagum biejerinckii pelagicum maris hiroshimense Oceanosprillum maris williamsae communis vaga haloplanktis rubra citrea esperjiana undina aurantia putrifaciens hanedai luteoviolaceae denitrificans tetradonis Alteromonas colwelliana 1972 1973 1976 1977 1978 1979 1981 1982 1984 1986 1987 1988 1990 colwelliana putrifaciens (T) communis (T) linum (T) macleodii (T) nomenclature

43. vagabenthica hanedai colwelliana algae MarinomonasShewanella communis vaga haloplanktis rubra citrea esperjiana undina aurantia putrifaciens hanedai luteoviolaceae denitrificans tetradonis atlantica carageenovora Alteromonas colwelliana 1972 1973 1976 1977 1978 1979 1981 1982 1984 1986 1987 1988 1990 1992 japonicum minutium biejerinckii maris hiroshimense multiglobiferum pelagicum pusillum commune jannaschii kreigii vagum biejerinckii pelagicum maris hiroshimense Oceanosprillum maris williamsae putrifaciens (T) communis (T) linum (T) macleodii (T) nomenclature

44. vagabenthica hanedai colwelliana algae MarinomonasShewanella communis vaga haloplanktis putrifaciens hanedai denitrificans rubra citrea esperjiana undina aurantia luteoviolaceae tetradonis atlantica carageenovora Alteromonas colwelliana 1972 1973 1976 1977 1978 1979 1981 1982 1984 1986 1987 1988 1990 1992 1995 japonicum minutium biejerinckii maris hiroshimense multiglobiferum pelagicum pusillum commune jannaschii kreigii vagum biejerinckii pelagicum maris hiroshimense Oceanosprillum maris williamsae distincta fulginea atlantica aurantia carrageenovora citrea esperjiana luteoviolacea nigrifaciens pisicida rubra haloplanktis haloplanktis (T) Pseudoalteromonas undina haloplanktis tetradonis putrifaciens (T) communis (T) linum (T) macleodii (T) nomenclature

45. vagabenthica hanedai colwelliana algae MarinomonasShewanella communis vaga haloplanktis rubra citrea esperjiana undina aurantia putrifaciens hanedai luteoviolaceae denitrificans tetradonis atlantica carageenovora Alteromonas colwelliana 1972 1973 1976 1977 1978 1979 1981 1982 1984 1986 1987 1988 1990 1992 1995 1997 japonicum minutium biejerinckii maris hiroshimense multiglobiferum pelagicum pusillum commune jannaschii kreigii vagum biejerinckii pelagicum maris hiroshimense Oceanosprillum maris williamsae distincta fulginea atlantica aurantia carrageenovora citrea esperjiana luteoviolacea nigrifaciens pisicida rubra Pseudoalteromonas undina antartica elyakoviii haloplanktis tetradonis haloplanktis haloplanktis (T) putrifaciens (T) communis (T) linum (T) macleodii (T) nomenclature

46. vagabenthica hanedai colwelliana algae MarinomonasShewanella communis vaga haloplanktis rubra citrea esperjiana undina aurantia putrifaciens hanedai luteoviolaceae denitrificans tetradonis atlantica carageenovora Alteromonas colwelliana 1972 1973 1976 1977 1978 1979 1981 1982 1984 1986 1987 1988 1990 1992 1995 1997 2000 japonicum minutium biejerinckii maris hiroshimense multiglobiferum pelagicum pusillum commune jannaschii kreigii vagum biejerinckii pelagicum maris hiroshimense Oceanosprillum maris williamsae distincta fulginea atlantica aurantia carrageenovora citrea esperjiana luteoviolacea nigrifaciens pisicida rubra Pseudoalteromonas undina antartica elyakoviii fridgidimarina geldimarina woodyii amazonensis baltica oneidensis pealeana violacea bacteriolytica prydzensis tunicata distincta elyakovii peptidolytica haloplanktis tetradonis mediterannea haloplanktis haloplanktis (T) putrifaciens (T) communis (T) linum (T) macleodii (T) nomenclature

47. vagabenthica hanedai colwelliana algae MarinomonasShewanella communis vaga haloplanktis rubra citrea esperjiana undina aurantia putrifaciens hanedai luteoviolaceae denitrificans tetradonis atlantica carageenovora Alteromonas colwelliana 1972 1973 1976 1977 1978 1979 1981 1982 1984 1986 1987 1988 1990 1992 1995 1997 2000 2001 japonicum minutium biejerinckii maris hiroshimense multiglobiferum pelagicum pusillum commune jannaschii kreigii vagum biejerinckii pelagicum maris hiroshimense Oceanosprillum maris williamsae distincta fulginea atlantica aurantia carrageenovora citrea esperjiana luteoviolacea nigrifaciens pisicida rubra Pseudoalteromonas undina antartica elyakoviii fridgidimarina geldimarina woodyii amazonensis baltica oneidensis pealeana violacea bacteriolytica prydzensis tunicata distincta elyakovii peptidolytica tetrodonis japonica haloplanktis tetradonis mediterannea haloplanktis haloplanktis (T) putrifaciens (T) communis (T) linum (T) macleodii (T) nomenclature

48. vagabenthica hanedai colwelliana algae MarinomonasShewanella communis vaga haloplanktis rubra citrea esperjiana undina aurantia putrifaciens hanedai luteoviolaceae denitrificans tetradonis atlantica carageenovora Alteromonas colwelliana 1972 1973 1976 1977 1978 1979 1981 1982 1984 1986 1987 1988 1990 1992 1995 1997 2000 2001 2002 japonicum minutium biejerinckii maris hiroshimense multiglobiferum pelagicum pusillum commune jannaschii kreigii vagum biejerinckii pelagicum maris hiroshimense Oceanosprillum maris williamsae distincta fulginea Pseudoalteromonas elyakoviii fridgidimarina geldimarina woodyii amazonensis baltica oneidensis pealeana violacea japonica denitrificans livingstonensis alleyanna atlantica aurantia carrageenovora citrea esperjiana luteoviolacea nigrifaciens pisicida rubra undina antartica bacteriolytica prydzensis tunicata distincta elyakovii peptidolytica tetrodonis haloplanktis tetradonis mediterannea haloplanktis haloplanktis (T) putrifaciens (T) communis (T) linum (T) macleodii (T) nomenclature

49. vagabenthica hanedai colwelliana algae MarinomonasShewanella communis vaga haloplanktis rubra citrea esperjiana undina aurantia putrifaciens hanedai luteoviolaceae denitrificans tetradonis atlantica carageenovora Alteromonas colwelliana 1972 1973 1976 1977 1978 1979 1981 1982 1984 1986 1987 1988 1990 1992 1995 1997 2000 2001 2002 2004 japonicum minutium biejerinckii maris hiroshimense multiglobiferum pelagicum pusillum commune jannaschii kreigii vagum biejerinckii pelagicum maris hiroshimense Oceanosprillum maris williamsae distincta fulginea Pseudoalteromonas elyakoviii fridgidimarina geldimarina woodyii amazonensis baltica oneidensis pealeana violacea japonica denitrificans livingstonensis alleyanna atlantica aurantia carrageenovora citrea esperjiana luteoviolacea nigrifaciens pisicida rubra undina antartica bacteriolytica prydzensis tunicata distincta elyakovii peptidolytica tetrodonis haloplanktis tetradonis 11 others mariniintestina saire schlegeliana gaetbuli mediterannea primoryensis haloplanktis haloplanktis (T) putrifaciens (T) communis (T) linum (T) macleodii (T) nomenclature

50. name taxon combined name exemplar nomos journal article gene annotation any online information strain record links from the web journal article strain record gene annotation journal article links to the web DOI (2) Names for Life: illustration of solution

51. dissemination nametaxon combined name exemplar nomos By reasoning over information objects, construct services that can be offered through multiple resolution. Look up this name and all its synonyms in PubMed Determine whether this exemplar is part of a taxon in another nomos Compare this name to the current state (contents) of the taxon (2) Names for Life: illustration of solution doi>

52. Paskin, Norman. "Digital Object Identifiers for scientific data". Paper presented at 19th International CODATA Conference, Berlin, 10 November 2004. http://www.doi.org/topics/041110CODATAarticleDOI.pdf Project announced to develop DOIs for scientific data: http://www.doi.org/news/TIBNews.html Garrity, G. M.; Lyons, C. "Future-proofing biological nomenclature". Omics, 2003, Volume 7, Number 1, pgs. 31-33. pre version at http://www.eecs.umich.edu/~jag/wdmbio/garrity.htm. Harris, Jerald D. ""Published Works" in the electronic age: recommended amendments to Articles 8 and 9 of the Code". Bulletin of Zoological Nomenclature, 61(3), September 2004, pp. 138-148. "Online Registries: The DNS and Beyond...", Esther Dyson, Release 1.0 September 2003. [ print only: summary at doi:10.1340/309registries ] DOI progress report : D Lib magazine (online) [http://www.dlib.org/dlib/june03/paskin/06paskin.html] “Identification and Metadata: Components of DRM Systems" Norman Paskin; in E. Becker et al (eds) "Digital Rights Management” in the series Lecture Notes in Computer Science (Springer-Verlag, 2003) pp. 26-61 [http://www.doi.org/topics/drm_paskin_20030113_b1.pdf] DOI factsheets etc. http://www.doi.org/factsheets.html Further reading

53. doi> n.paskin@doi.org www.doi.org