Research of 3-Tier Mobility Stations System with bike and car sharing— Case study of small–scale city in GermanyWei Wang, Shun Su, Mengying Fu, Yonsorena Nong, Thomas Scriba and Dimas Numan FadhilE3S Web Conf., 145 (2020) 02017DOI: https://doi.org/10.1051/e3sconf/202014502017