Prohp, T.P., K.E. Ekpo, E.V. Osagie, A. Osagie, and H. Obi. 2009. “Polyphenol Contents and Polyphenol Oxidase Activities of Some Nigerian Kolanuts”. Pakistan Journal of Nutrition 8 (7): 1030–1031. https://doi.org/10.3923/pjn.2009.1030.1031.