Jovanović, B., Mostarac, K., Šarac, D. and Rakić, E. 2015. Express Services Market Analysis Based on the Lotka-Volterra Model – Case Study Serbia. Promet - Traffic&Transportation. 27, 2 (Apr. 2015), 173-180. DOI:https://doi.org/10.7307/ptt.v27i2.1608.