T. Djekić, S. Ristić, S. Stamenković, R. Šajn, and M. Engelman, “LICHENS AS INDICATORS OF AIR QUALITY IN BALNEOLOGICAL CENTER PROLOM BANJA (SOUTHERN SERBIA)”, J. Geogr. Inst. Cvijic, vol. 70, no. 2, pp. 101–113, Oct. 2020.