Não informado. (2011). Railway Signaling and Communications. Simmons Boardman Publishing.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Railway Signaling and Communications. Chicago, Ill: Simmons Boardman Publishing, 2011.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Railway Signaling and Communications. Simmons Boardman Publishing, 2011.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.