1. Deep and shallow banding of phosphorus and potassium as alternatives to broadcast fertilization for no-till corn;Bordoli;Agron. J.,1998
2. Braun, A.R., Smaling, E.M.A., Muchugu, E.I., Shepherd, K.D., Corbett, J.D., 1997. Maintenance and Improvement of Soil Productivity in the Highlands of Ethiopia, Kenya, Madagascar and Uganda: An Inventory of Spatial and Non-spatial Survey and Research Data on Natural Resources and Land Productivity. African Highlands Initiative Technical Report Series. International Centre for Research in Agroforestry, Nairobi, Kenya.
3. From Agronomic Data to Farmer Recommendations: An Economics Training Manual;CIMMYT,1988
4. Cong, P.T., 2000. Improving phosphorus availability in selected soils from the uplands of South Vietnam by residue management. A case study: Tithonia divesifolia. PhD Dissertation. Department of Earth and Environmental Sciences. Katholieke Universiteit, Leuven, Belgium.
5. Improving phosphorus availability in two upland soils of Vietnam using Tithonia diversifolia H.;Cong;Plant Soil,2005