WASET
    Justina I. R. Udotong and  Ime R. Udotong and  Offiong U. Eka,  Spatio-temporal Variations in Heavy Metal Concentrations in Sediment of Qua Iboe River Estuary, Nigeria.   journal   = {International Journal of Environmental and Ecological Engineering}, [online]. World Academy of Science, Engineering and Technology.
    June 2015, vol. 102(6). 681 - 685
    [viewed 25 April 2024]. Available from: https://publications.waset.org/pdf/10001538.