Mihajlović, Jovan, Vladan Ducić, and Dragan Burić. “TORNADO FREQUENCY IN THE USA — METEOROLOGICAL AND NON-METEOROLOGICAL FACTORS OF A DOWNWARD TREND”. Journal of the Geographical Institute “Jovan Cvijić” SASA 65, no. 3 (December 31, 2015): 269–280. Accessed October 16, 2021. https://ojs.gi.sanu.ac.rs/index.php/zbornik/article/view/277.