Thepporn Jaroenroy และ Chutarat Chompunth. (2019) Safety, occupational health and environmental management system model for small and medium-sized enterprises. National Institute of Development Administration:ม.ป.ท.Thepporn Jaroenroy และ Chutarat Chompunth. 2019. Safety, occupational health and environmental management system model for small and medium-sized enterprises. ม.ป.ท.:National Institute of Development Administration;Thepporn Jaroenroy และ Chutarat Chompunth. Safety, occupational health and environmental management system model for small and medium-sized enterprises. ม.ป.ท.:National Institute of Development Administration, 2019. Print.