Machete, James, and Ricks Chabo. “A Review of Piggery Manure Management: Generally, across Western, Asian and African Countries”. Botswana Journal of Agriculture and Applied Sciences 14, no. 1 (April 3, 2020): 17-27. Accessed July 24, 2021. https://bojaas.buan.ac.bw/index.php/jaas/article/view/17.