B.T. Rang, F.K. Akinnifesi, and D.O. Ladipo. “PERFORMANCE OF SELECTED WOODY AGROFORESTRY SPECIES GROWN ON AN ALFISOL AND AN ULTISOL IN THE HUMID LOWLAND OF WEST AFRICA, AND THEIR EFFECTS ON SOIL PROPERTIES”. Journal of Tropical Forest Science (JTFS), vol. 7, no. 2, Dec. 1994, pp. 303-12, https://jtfs.frim.gov.my/jtfs/article/view/1824.