WASET
    N. Sapari and  S. Mustapha and  H. Jusoh,  Enhancing Landfill Gas Production by Methanogenic Sand Layer.   journal   = {International Journal of Civil and Environmental Engineering}, [online]. World Academy of Science, Engineering and Technology.
    December 2011, vol. 60(12). 766 - 773
    [viewed 26 April 2024]. Available from: https://publications.waset.org/pdf/10280.