Hoang Nghia Duyet, Nguyen Dinh Son, Nguyen Van An and Truong Thi Thuan 2003: Effect of high dietary levels of sweet potato leaves on the reproductive performance of pure and crossbred Mong Cai sows. Livestock Research for Rural Development. Volume 15, Article #43. Retrieved , from http://www.lrrd.org/lrrd15/6/duye156.htm