Bradford C. Snell 1974: American Ground Transport: A Proposal for Restructuring the Automobile, Truck, Bus and Rail Industries. Report presented to the Committee of the Judiciary, Subcommittee on Antitrust and Monopoly, United States Senate, February 26, 1974, United States Government Printing Office, Washington, 1974, pp. 16-24. Sporvognsrejser Dansk side med bilder av trikk Utdanning.no sin yrkesbeskrivelse av trikkefører William D. Middleton (1967): The Interurban Era. Milwaukee: Kalmbach Publishing. ISBN 0-89024-013-2.