R. Panyatanakun, U. Teeravuttichai, S. Siriphanich, and A.- on Aungsuratana, “Basic Data for Landscape Planning, Hin-Perng Rafting Area, Sai Yai River, Khao-Yai National Reserved Forests”, kasetsart J. Soc. Sci., vol. 22, no. 2, pp. 165–178, Jul. 2001.