WASET
    E. Al-Essa and  R. Bello-Mendoza and  D. G. Wareham,  The Effect of Magnetite Particle Size on Methane Production by Fresh and Degassed Anaerobic Sludge.   journal   = {International Journal of Environmental and Ecological Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2020, vol. 158(2). 63 - 66
    [viewed 16 April 2024]. Available from: https://publications.waset.org/pdf/10011043.