Kogram, Chanlong, Somjai Kowsurat, Boonluer Srimoongkoon, and Wongduen Prasomthong. “Effect of Sowing Date on Yield Component, Biomass Yield and Nutrient Content in Cowpea”. Thai Agricultural Research Journal 22, no. 1 (March 28, 2004): 2–8. accessed September 30, 2026. https://li01.tci-thaijo.org/index.php/thaiagriculturalresearch/article/view/212202.