Al-Qahtani, Ahmed Ali, et al. “Phylogenetic and Nucleotide Sequence Analysis of Influenza A (H1N1) HA and NA Genes of Strains Isolated from Saudi Arabia”. The Journal of Infection in Developing Countries, vol. 11, no. 01, Jan. 2017, pp. 81-88, doi:10.3855/jidc.9259.