Authors: Bernard, R.T. & Frankwell W. Dulle

Authors: H. A. Haji & A. M. Omar

Authors: Alloys Mvuma, Anthony Faustine, Deo Shao, Hassan Seif, Rukia Mwifunyi and Steven Edward

Author: Deo Shao

Author: Isaac Safari

Authors: Doris S. Matovelo, Jangawe Msuya  and Egbert Desmet

Author: Maulid Dotto

Author: Lucian Ngeze

Author: Doris S. Matovelo