Infection of nonhuman primates with recombinant human metapneumovirus lacking the SH, G, or M2-2 protein categorizes each as a nonessential accessory protein and identifies vaccine candidates - Biacchesi,S.; Pham,Q.N.; Skiadopoulos,M.H.; Murphy,B.R.; Collins,P.L.; Buchholz,U.J. (J Virol, 2005)