Kalvig, Per, Niels Fold, Jesper Bosse Jønsson, and Elisante Elisaimon Mshiu. “Rock Phosphate and Lime for Small-Scale Farming in Tanzania, East Africa”. GEUS Bulletin 26 (July 10, 2012): 85–88. Accessed March 29, 2024. https://geusbulletin.org/index.php/geusb/article/view/4772.