Petryk, Agnieszka, Marek Ryczek, and Sylwia Guzdek. “Evaluation of the Effect of Using Sewage Sludge As a Fertilizer on the Concentration of Heavy Metals in Soil and the Economic Implications of Its Application ”. Economics and Environment 88, no. 1 (April 16, 2024): 647. Accessed April 3, 2025. https://ekonomiaisrodowisko.pl/journal/article/view/647.