Chumworathayi, P. “Standard Time Study and Manpower Determination in the Outpatient Dispensing Service at Srinagarind Hospital”. Srinagarind Medical Journal, vol. 23, no. 1, Nov. 2013, pp. 53-65, https://li01.tci-thaijo.org/index.php/SRIMEDJ/article/view/13053.