Pookpakdi, Aphiphan, and Veerachai Sriwatanapongse. 1985. “Soybean in Cropping System in Central Thailand II. Various Intercropping Combinations of Corn and Soybean”. Agriculture and Natural Resources 19 (2). Bangkok, Thailand:151-54. https://li01.tci-thaijo.org/index.php/anres/article/view/242433.