Não informado. (2011). Railway Signaling. Simmons Boardman Publishing.
Chicago-Zitierstil (17. Ausg.)Não informado. Railway Signaling. Chicago, Ill: Simmons Boardman Publishing, 2011.
MLA-Zitierstil (8. Ausg.)Não informado. Railway Signaling. Simmons Boardman Publishing, 2011.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.