@BOOK {KANG:1995c, title = {Fertilizers; definitions and calculations: IITA research guide, No. 24}, author = {Kang, B. T. }, series = {IITA research guide, No. 24}, year = {1995}, month = {July}, publisher = {International Institute of Tropical Agriculture (IITA)}, address = {Ibadan, Nigeria}, note = {28p.}, }