Ahmadu, A. A., P. Tarimaledei, and A. A. Onanuga. “TRITERPENOIDS FROM GUTENBERGIA NIGRITANA(BENTH).OLIV AND HIERN”. African Journal of Traditional, Complementary and Alternative Medicines, vol. 10, no. 3, Mar. 2013, pp. 405-9, https://journals.athmsi.org/index.php/ajtcam/article/view/1619.