แก้วแปงจันทร์ ภ. “Relations Between the Timing of Birth and Obstetric Perineal Wound Infection”. Journal of Nakornping Hospital, vol. 8, no. 1, July 2019, pp. 15-24, https://he01.tci-thaijo.org/index.php/jnkp/article/view/205214.