Allen, C. F. (2015). Railroard curves and earthwork.
Cita Chicago Style (17a ed.)Allen, Calvin Frank. Railroard Curves and Earthwork. 2015.
Cita MLA (9a ed.)Allen, Calvin Frank. Railroard Curves and Earthwork. 2015.
Precaución: Estas citas no son 100% exactas.