An, Le Van, et al. “Molecular Characterization of Influenza A(H1N1)pdm09 Virus Circulating During the 2009 Outbreak in Thua Thien Hue, Vietnam”. The Journal of Infection in Developing Countries, vol. 7, no. 03, Mar. 2013, pp. 235-42, doi:10.3855/jidc.2883.