Pimentel Vasconcelos, A. L., Maia Seco, Álvaro J. and César Bastos Silva, A. M. (1) “Comparison of Procedures to Estimate Critical Headways at Roundabouts”, Promet - Traffic&Transportation, 25(1), pp. 43-53. doi: 10.7307/ptt.v25i1.1246.