Nathakitt Puangchit และ Chanchai Yarwudhi. (2007) The modeling of forest road standards for Khao Yai national park, Thailand. Kasetsart University,:ม.ป.ท.Nathakitt Puangchit และ Chanchai Yarwudhi. 2007. The modeling of forest road standards for Khao Yai national park, Thailand. ม.ป.ท.:Kasetsart University,;Nathakitt Puangchit และ Chanchai Yarwudhi. The modeling of forest road standards for Khao Yai national park, Thailand. ม.ป.ท.:Kasetsart University, 2007. Print.