Palapan Kampan. (1998) The effects of short-course occupational training on seasonal migration, employment and income. National Institute of Development Administration,:ม.ป.ท.Palapan Kampan. 1998. The effects of short-course occupational training on seasonal migration, employment and income. ม.ป.ท.:National Institute of Development Administration,;Palapan Kampan. The effects of short-course occupational training on seasonal migration, employment and income. ม.ป.ท.:National Institute of Development Administration, 1998. Print.