Pramote Charongrattanasakul, and Adisak Pongpullponsak. “Minimizing The Cost of an Integrated Model by EWMA Control Chart”. Agriculture and Natural Resources, vol. 43, no. 5, Dec. 2009, pp. 385-91, https://li01.tci-thaijo.org/index.php/anres/article/view/244847.