Não informado. (2011). Railway Signaling and Communications. Simmons Boardman Publishing.
Chicago-referens (17:e uppl.)Não informado. Railway Signaling and Communications. Chicago, Ill: Simmons Boardman Publishing, 2011.
MLA-referens (8:e uppl.)Não informado. Railway Signaling and Communications. Simmons Boardman Publishing, 2011.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.