Srithawong, A., P. Poncumhak, S. Ladawan, P. Phrompao, S. Konsanit, and T. Promsrisuk. “Reference Value of Peak Cough Flow in Thai Subjects Aged 20-90 Years”. Archives of Allied Health Sciences, vol. 31, no. 3, Dec. 2019, pp. 337-46, https://he01.tci-thaijo.org/index.php/ams/article/view/233158.