1. https://news.thomasnet.com/fullstory/gps-receiver-provides-20-hz-update-rate-587490
2. https://opendata.cityofnewyork.us/
3. Didichuxing.
https://gaia.didichuxing.com/
4. Uber.
https://www.uber.com/
5. Bast, H., Funke, S., Matijević, D.: Transit: ultrafast shortest-path queries with linear-time preprocessing. In: 9th DIMACS Implementation Challenge-Shortest Path (2006)