A. Olszańska, A. S. Kowalska, K. Paskudzka, and J. Szymańska, “Regional differentiation of changes in pig livestock procurement in Poland in 1999–2022 in the context of economic and environmental conditions”, EiS, vol. 97, no. 2, p. 1143, May 2026, doi: 10.34659/eis.2026.97.2.1143.