S. . Iamsirithaworn, P. . Akarasewi, T. . Yingyong, S. . Suthachana, C. . Pittayawonganon, and K. . Ungchusak, “Three Waves of the 2009 H1N1 Infl uenza Pandemic in Thailand”, Siriraj Med J, vol. 63, no. 2, pp. 64–67, Apr. 2020.