Trung, Nguyen Thanh, Sutkhet Nakasathien, and Vichan Vichukit. 2013. “Enhancing Sustainable Cassava Production in Hilly Areas of Van Yen, Yen Bai Province, Vietnam”. Agriculture and Natural Resources 47 (4). Bangkok, Thailand:492-505. https://li01.tci-thaijo.org/index.php/anres/article/view/243089.