Brian H. Marsh,  An Investigation of Current Potato Nitrogen Fertility Programs' Contribution to Ground Water Contamination.   journal   = {International Journal of Agricultural and Biosystems Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2016, vol. 111(3). 138 - 144
    [viewed 09 May 2021]. Available from: https://publications.waset.org/pdf/10003813.