1. Di Liu, Weifeng Shi, George F Gao
Poultry carrying H9N2 act as incubators for novel human avian influenza viruses 
Di Liu, Weifeng Shi, George F Gao 
The Lancet 
Volume 383, Issue 9920, (March 2014)
DOI: /S (14)60386-X
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2. Figure
Phylogenetic trees of PB1 gene (an example of an H9N2 reassorted gene)
Distinct subtypes of influenza virus are shown. Human isolates are noted with blue dots. Evolutionary distances were calculated with use of the maximum likelihood method.
The Lancet  , DOI: ( /S (14)60386-X)
Copyright © 2014 Elsevier Ltd Terms and Conditions