Characterization of low-pathogenicity H5N1 avian influenza viruses from North America - Spackman, Erica; Swayne, D.; Suarez, D.; Senne, D.; Pedersen, J.; Killian, M.; Pasick, J.; Handel, K.; Pillai, Segaran; Lee, C.; Stallknecht, D.; Slemons, R.; et al. (Journal of Virology, 2007)