Charles Mbohwa and  Alexander Mudiwakure,  Sustainable and Ecological Designs of the Built Environment.   journal   = {International Journal of Energy and Environmental Engineering}, [online]. World Academy of Science, Engineering and Technology.
    April 2013, vol. 76(4). 314 - 321
    [viewed 19 September 2020]. Available from: https://publications.waset.org/pdf/826.