Siddig, N., A. Ahmed, S. Saad, and F. Koua. “Heavy Metals Accumulation from Sewage Sludge in the Nile Tilapia Oreochromis Niloticus (Trewavas, 1983) During a Sludge-Earthworm-Fish Short-Term Cycling”. Italian Journal of Food Safety, Vol. 8, no. 1, Mar. 2019, doi:10.4081/ijfs.2019.7257.