1) Farideh Ramjerdi: The Norwegian experience with Electronic Toll Rings, Proceedings of the Int'l Conferenceon Advanced Technologies in Transportation andTraffic Management, pp.135-142, 1994
2) Michael Cewers: Stockholm toll collection system, Proceedings of the Int'l Conference on AdvancedTechnologies in Transportation and Traffic Management, pp.143-150, 1994
3) Joseph Yee: The need for advanced technology in roadpricing-the Singapore experience, Proceedings of the Int'l Conference on Advanced Technologies in Transportationand Traffic Management, pp.129-134, 1994