Citation 1324
Webby RJ, Rossow K, Erickson G, Sims Y, and Webster R. 2004. Multiple lineages of antigenically and genetically diverse influenza A virus co-circulate in the United States swine population. Virus Research 103:67-73.
http://BirdFluBook.org/resources/webby67.pdf.
http://BirdFluBook.org/resources/webby67.pdf.