CHUEKWON, K., and S. BOONLUM. “Association of Prolactin Gene With Egg Production in Khaki Campbell Ducks”. Walailak Journal of Science and Technology (WJST), vol. 14, no. 11, Mar. 2016, pp. 849-53, https://wjst.wu.ac.th/index.php/wjst/article/view/1934.