WASET
    Maris Klavins and  Valery Rodinov,  Long Term Changes of Water Quality in Latvia.   journal   = {International Journal of Environmental and Ecological Engineering}, [online]. World Academy of Science, Engineering and Technology.
    June 2017, vol. 127(7). 640 - 645
    [viewed 19 April 2024]. Available from: https://publications.waset.org/pdf/10007587.