The Rand paper series. RAND Corporation. 1970. p. 16. „Potentially more effective in the near term would be the use of direct road pricing to make freight journeys more expensive on congested routes or to influence the time of day at which freight traffic operates“
Peirce, Sean; Puckett, Sean; Petrella, Margaret; Minnice, Paul; Lappin, Jane (2013). „Effects of Full-Facility Variable Tolling on Traveler Behavior: Evidence from a Panel Study of the Sr-520 Corridor in Seattle, Washington“. Transportation Research Record: Journal of the Transportation Research Board (anglų). 2345: 74–82. doi:10.3141/2345-10. S2CID109715156.
Agarwal, Sumit; Koo, Kang Mo (2016-09-01). „Impact of electronic road pricing (ERP) changes on transport modal choice“. Regional Science and Urban Economics. 60: 1–11. doi:10.1016/j.regsciurbeco.2016.05.003. ISSN0166-0462.
Peirce, Sean; Puckett, Sean; Petrella, Margaret; Minnice, Paul; Lappin, Jane (2013). „Effects of Full-Facility Variable Tolling on Traveler Behavior: Evidence from a Panel Study of the Sr-520 Corridor in Seattle, Washington“. Transportation Research Record: Journal of the Transportation Research Board (anglų). 2345: 74–82. doi:10.3141/2345-10. S2CID109715156.
Agarwal, Sumit; Koo, Kang Mo (2016-09-01). „Impact of electronic road pricing (ERP) changes on transport modal choice“. Regional Science and Urban Economics. 60: 1–11. doi:10.1016/j.regsciurbeco.2016.05.003. ISSN0166-0462.