Adisak Sajjapongse and M.H. Wu (1989) “Effect of Some Climatic Factors on Sweet Potato Yield”, Agriculture and Natural Resources. Bangkok, Thailand, 23(1), pp. 86–92. available at: https://li01.tci-thaijo.org/index.php/anres/article/view/242282 (accessed: 18 September 2026).