For more information please read:

Ed Strauss & Karen Strauss - The Bus World Encyclopedia of Buses

G.N. Georgano & G. Marshall Naul - The Complete Encyclopedia of Commercial Vehicles

Albert Mroz - Illustrated Encyclopedia of American Trucks & Commercial Vehicles

Donald F. Wood - American Buses

Denis Miller - The Illustrated Encyclopedia of Trucks and Buses

Susan Meikle Mandell - A Historical Survey of Transit Buses in the United States

David Jacobs - American Buses, Greyhound, Trailways and Urban Transportation

William A. Luke & Linda L. Metler - Highway Buses of the 20th Century: A Photo Gallery 

William A. Luke & Brian Grams - Buses of Motorcoach Industries 1932-2000 Photo Archive

William A. Luke - Greyhound Buses 1914-2000 Photo Archive

William A. Luke - Prevost Buses 1924-2002 Photo Archive

William A. Luke - Flxible Intercity Buses 1924-1970 Photo Archive

William A. Luke - Buses of ACF Photo Archive (including ACF-Brill & CCF-Brill)

William A. Luke - Trailways Buses 1936-2001 Photo Archive

William A. Luke - Fageol & Twin Coach Buses 1922-1956 Photo Archive

William A. Luke - Yellow Coach Buses 1923 Through 1943: Photo Archive

William A. Luke - Trolley Buses: 1913 Through 2001 Photo Archive

Harvey Eckart - Mack Buses: 1900 Through 1960 Photo Archive

Brian Grams & Andrew Gold - GM Intercity Coaches 1944-1980 Photo Archive

Robert R. Ebert  - Flxible: A History of the Bus and the Company

John McKane - Flxible Transit Buses: 1953 Through 1995 Photo Archive

Bill Vossler - Cars, Trucks and Buses Made by Tractor Companies

Lyndon W Rowe - Municipal buses of the 1960s

Edward S. Kaminsky - American Car & Foundry Company 1899-1999

Dylan Frautschi - Greyhound in Postcards: Buses, Depots and Post Houses