1. Aguirre, G., J. Calderon, D. Buitrago, V. Iriarte, J. Ramos, J. Blajos, G. Thiele, and A. Devaux. 1999. Rustic seedbeds: a bridge between formal and traditional potato seed systems in Bolivia. Impact on a changing world; International Potato Center Program Report 1997/ 1998. Lima: CIP.
2. Cassaday, K. 1988. From agronomic data to farmer recommendations: an economics training manual. Mexico: CIMMYT.
3. Crissman, C.C., L.M. Crissman, and C. Carli. 1993. Seed potato systems in Kenya: a case study. Lima: CIP.
4. Elphinstone, J.G. 2005. The current bacterial wilt situation: a global overview. In Bacterial wilt disease and the Ralstonia solanacearum species complex, ed. C. Allen, P. Prior, and A.C. Hayward, 9–28. St. Paul: APS.
5. Eshetu, M., O.E. Ibrahim, and B. Etenesh. 2005. Improving potato seed tuber quality and producers’ livelihoods in Hararghe, Eastern Ethiopia. Journal of New Seeds 7(3): 31–56.