1. https://moovit.com/blog/history-public-transport/
2. Shaheen, S.A. Finson, R.: Intelligent transportation systems. In: Cleveland, C.J. (ed.) Encyclopedia of Energy, pp. 487–496. Elsevier (2004) ISBN 9780121764807
3. https://en.wikipedia.org/wiki/Public_transport
4. Humphreys, P.: City transport in the 2020s. Transport and Travel. Archived from the original on 2 February 2017. Retrieved 20 January 2017
5. https://transportandtravel.wordpress.com/2016/12/17/city-transport-in-the-2020s/