Khan, Haseeb Ahmed, et al. “COMPARISON OF SALIVARY ALPHA-AMYLASE LEVELS IN SCHIZOPHRENICS AND NORMAL INDIVIDUALS”. Pakistan Journal of Physiology, vol. 15, no. 1, Mar. 2019, pp. 7-9, https://pjp.pps.org.pk/index.php/PJP/article/view/1073.