Nessa, A., S. Rahmana, M. Chowdhury, and Z. Parveen. “Effects of Sewage Sludge at Different PH Levels on Ipomoea Aquatica”. Bangladesh Journal of Scientific and Industrial Research, vol. 47, no. 1, May 2012, pp. 47-54, doi:10.3329/bjsir.v47i1.10721.