Raeesa Moolla and  Ryan S. Johnson,  Spatial Distribution of Ambient BTEX Concentrations at an International Airport in South Africa.   journal   = {International Journal of Environmental and Ecological Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2019, vol. 146(2). 43 - 50
    [viewed 19 November 2019]. Available from: https://publications.waset.org/pdf/10010015.