Sirikwin, S., Lohlaka, S. and Waradagwinyoo, S. (1994) “Evaluation of Titer E-Z Vaccine in Six-month Old Infants”, Journal of Health Science of Thailand, 3(2), pp. 140–144. Available at: https://thaidj.org/index.php/JHS/article/view/6190 (Accessed: 6December2025).