Peacock, T P, Benton, D J, James, J, Sadeyen, J R, Chang, P X, Sealy, J E, Bryant, J E, Martin, S R, Shelton, H, Barclay, W S, Iqbal, M, "Immune Escape Variants of H9N2 Influenza Viruses Containing Deletions at the Hemagglutinin Receptor Binding Site Retain Fitness In Vivo and Display Enhanced Zoonotic Characteristics", Journal of Virology, 2017