Ratyńska, H., Grodzki, M., Waldon, B. and Wachowiak, E. 2011. Introduction of Alien Tree Species and Its Influence on Floristical Composition and Vegetation Structure of Acidophilous Oak Forests: the Experimental Plots in the Zielonka Forest. Acta Universitatis Lodziensis. Folia Biologica et Oecologica. 7, (Dec. 2011), 177–190. DOI:https://doi.org/10.2478/v10107-009-0024-z.