RT Journal Article SR Electronic A1 Załoga, Elżbieta A1 Kowalska, Sylwia T1 JF Transport And Communications YR 2019 VO 7 IS 1 SP 61 OP 65 DO 10.26552/tac.C.2019.1.13 UL https://tac.uniza.sk/artkey/tac-201901-0013.php AB