A. H. Molla and A. Fakhru’l-Razi, Md. Zahangir Alam,. “Biotransformation of Domestic Wastewater Treatment Plant Sludge by Two-Stage Integrated Processes -Lsb & Ssb”. IIUM Engineering Journal, vol. 6, no. 1, Oct. 2012, doi:10.31436/iiumej.v6i1.383.