Walczak, Natalia, Mateusz Hammerling, Jerzy Bykowski, and Zbigniew Walczak. 2015. “Economic and Hydraulic Criteria for Maintenance of Good Condition of Drainage Ditches”. Journal of Agribusiness and Rural Development 35 (1), 137-46. https://doi.org/10.17306/JARD.2015.15.