1. Shared units/coupling

2. Task: Find shared references among papers Use this file which is in upper-lower case and only one author initial to somewhat reduce spelling variants Run Analyze/Shared units/coupling/Shared units Note to reduce n of coupled pairs you may set min number of shared units to be printed in the Min number box.

3. The cou-file has shared references in 1st column and doc numbers in 2nd and 3rd

4. Assume you want to add labels to the doc numbers. If author names (they often are many on each papers and they need to be standardized): 1. Make a new outfile based on AU-field 2. Run Edit out-files/Convert Upper Lower Case/Good for author cited author in out-file 3. Run Edit out-files/Keep only author’s 1st initial 4. Select the 1st-file and then double click here, indicate the source of labels to add.

5. 5. Select the cou-file 6. Run Add data classify/Add labels to freq-docnr-docnr pairs/…making freq-label-label 7. Answer Yes to swap (no direction here!) 8. Answer Yes to delete self-related pairs (if you wish!) 9. Answer Yes to delete pairs with overlapping sets (if you wish!)

6. Now, the cdd-file has authors names instead of doc numbers for the pairs as defined in the previous steps (7, 8, 9) Next, run Analyze/Add frequencies to sum all shared references for a given pair (that may occur several times)

7. The cit-file has it!

8. Run Edit out-files/Sort numeric/descending by first column, and you will get this!

9. Note: Before mapping with Pajek you could reduce the pairfile to the most productive authors. Put the names in the list, type a new filename in the box “Type new file name here”. Select the pair-file and run Analyze/Select pairs from pairlist.

10. Note: For normalization purposes you can add number of references to the cou-file: 1. Make an out-file bases on the NR-field (number of references) 2. Put the out-file in Type new file name here 3. Select the cou-file and run Add data classify/Add labels to freq-docnr-docnr/…making freq-docnr-label- docnr-label 4. This will make the ad2-file and open it in Excel and calculate Salton’s index as a normalized measure of coupling strength, e.g. for the first pair 69/(157*132) 1/2