Dr. Kala Devi Ramahsamy. “Oil Palm Waste - Sewage Sludge Compost As A Peat Substitute In A Soilless Potting Media for Chrysanthemum”. Global Journal of Science Frontier Research, vol. 12, no. D2, Jan. 2012, pp. 35-44, https://journalofscience.org/index.php/GJSFR/article/view/487.