Wansi, Jean Duplex; Djouaka Bavoua, Judith Liliane; Happi, Emmanuel Ngeufa; Devkota, Krishna Prasad; Lenta, Bruno Ndjakou; Mesaik, Muhammed Ahmed; Choudhary, Muhammad Iqbal; Fomum, Zacharias Tanee; Sewald, Norbert Zeitschrift fur Naturforschung - Section B Journal of Chemical Sciences, 2009 , vol. 64, # 4 p. 452 - 458