S. K. Appiah and  E. N. Aidoo and  D. Asamoah Owusu and  M. W. Nuonabuor,  Geostatistical Analysis of Contamination of Soils in an Urban Area in Ghana.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    June 2018, vol. 138(6). 139 - 147
    [viewed 12 November 2019]. Available from: https://publications.waset.org/pdf/10009292.