ZIELONKA, Dariusz, NIEREBIŃSKI, Mariusz, KALAJI, Hazem M., AUGUSTYNOWICZ, Janusz, PRĘDECKA, Anna and RUSSEL, Stefan. Efficiency of the photosynthetic apparatus in Cannabis sativa L. fertilized with sludge froma wastewater treatment plant and with phosphogypsum. Ecological Questions. Online. 15 February 2018. Vol. 28, pp. 55-61. [Accessed 8 July 2025]. DOI 10.12775/EQ.2017.039.