Puangsun, Sompon, and Klot Patanarapeelert*. 2018. “An SIR Epidemic Model with Gravity in Patchy Environment: Analyses for Two Patches System”. CURRENT APPLIED SCIENCE AND TECHNOLOGY 12 (2). Bangkok, Thailand:127-33. https://li01.tci-thaijo.org/index.php/cast/article/view/135748.