1. PhD, Iwona Kiniorska, PhD, Department of Mathematics and Natural Sciences, Institute of Geography, The Jan Kochanowski University in Kielce, ul. Świętokrzyska 15, 25–406 Kielce , Poland
2. Department of Mathematics and Natural Sciences, Institute of Geography, The Jan Kochanowski University in Kielce, ul. Świętokrzyska 15, 25–406 Kielce , Poland