Puapornpong, Pawin, Somchai Santiwatanakul, Wichian Manolerdthewan, and Maethaphan Kitporntheranunt. 2015. “The Prevalence of Group B Streptococcus in First and Third Trimester Pregnancy”. Journal of Medicine and Health Sciences 15 (1). https://he01.tci-thaijo.org/index.php/jmhs/article/view/61296.