Socio-Economic aspects of free public transportTuisk, Tarmo; Prause, Gunnar KlausReliability and Statistics in Transportation and Communication : Selected Papers from the 18th International Conference on Reliability and Statistics in Transportation and Communication, RelStat’18, 17-20 October 2018, Riga, Latvia2019 / p. 3-13 https://doi.org/10.1007/978-3-030-12450-2_1 Conference proceedings at Scopus Article at Scopus