Rajao, D. S., Anderson, T. K., Kitikoon, P., Stratton, J., Lewis, N. S., & Vincent, A. L. (2018). Antigenic and genetic evolution of contemporary swine H1 influenza viruses in the United States. Virology, 518, 45-54. https://doi.org/10.1016/j.virol.2018.02.006