Cockrell, N., & Cockrell, B. (1978). Roofs over rivers: A guide to Oregon's covered bridges. Touchstone Press.
Cita Chicago Style (17a ed.)Cockrell, Nick, y Bill Cockrell. Roofs over Rivers: A Guide to Oregon's Covered Bridges. Beaverton, Ore.: Touchstone Press, 1978.
Cita MLA (8a ed.)Cockrell, Nick, y Bill Cockrell. Roofs over Rivers: A Guide to Oregon's Covered Bridges. Touchstone Press, 1978.
Precaución: Estas citas no son 100% exactas.