Evaluation of the level of service of the public transport operator of Thessaloniki before and after its nationalizationNikolaos Kalteziotis, Ioannis Kalfopoulos, Evangelos Genitsaris, Aristotelis Naniopoulos and Dimitrios NalmpantisE3S Web Conf., 436 (2023) 11001DOI: https://doi.org/10.1051/e3sconf/202343611001