Piya Duangpatra. “A Study on the Relative Response of 3 Cassava Varieties to Chemical Fertilizers and Weeding Methods”. Agriculture and Natural Resources 24, no. 4 (December 30, 1990): 424–438. accessed August 29, 2026. https://li01.tci-thaijo.org/index.php/anres/article/view/242236.