Zomboudre, G., Ouedraogo, M., Guinko, S. and Macauley, H.R. (2005) Physiological response and crop productivity in traditional agroforestry system: The case of maize associated with shea butter in the east zone of Burkina Faso. Biotechnology, Agronomy, Society and Environment, 9, 75-85.
 Maiga, A. (1987) Trees in traditional agroforestry system in Bazega province. Influence of Vitellaria paradoxa, Parkia biglobosa and Acacia albida on the sorghum and millet. Intership Report, IRBET/CNRST, Ouagadougou, 86.
 Gnanglè, P.C. (2005) Shea parklands in Benin: Sociocultural importance, morphological characterization, structural and natural regeneration. Master Thesis, Management of Natural Resources, UAC/FSA, Abomey-Calavi, 113.
 Gbemavo, D.S.J.C., Glèlè Kaka?, R., Assogbadjo, A.E., Katary, A. and Gnanglè, P. (2010) Effect of shea trees shadiness on cotton capsular yield in shea butter treescotton agroecosystems of northern Benin. Tropicultura, 28, 193-199.
 Louppe, D. and Ouattara, N.K. (1997) Shea butter influence on the agricultural production in northern of Ivory Coast. XIth World Forestry Congress, Antalya, Turkey, Montpellier, CIRAD-Forêt, 13-22 October 1997, 11, 10- 13.
 Akpo, L.E. (1998) Trees effect on herbaceous vegetation in some plant communities in Senegal. Variation along climatic gradient. Ph.D. Thesis, Natural Science, Faculty of Technology Science—University of Cheikh Aanta Diop, Dakar, 133.
 Tomlinson, H., Teklehaimanot, Z., Traore A. and Olapade, E. (1995) Soil amelioration and root symbioses of Parkia biglobosa (Jacq.) Benth. in West Africa. Agroforestry Systems, 30,145-159. doi:10.1007/BF00708918
 Bayala, J., Teklehaimanot, Z. and Ouedraogo, J.S. (2002) Millet production under pruned tree crowns in a parkland system in Burkina Faso. Agroforestry Systems, 54, 203- 214. doi:10.1023/A:1016058906682