Berta-Szabó, E., Zsigrai, G., Szabó, A., & Loch, J. (2010). Effects of long-term K fertilization and liming on the extractable and exchangeable K contents of a Haplic Phaeosem soil. Acta Agraria Debreceniensis, I, 141-145. https://ojs.lib.unideb.hu/actaagrar/article/view/8392