Products Overview. XCOR Aerospace, archiviert vom Original (nicht mehr online verfügbar) am 25. November 2010; abgerufen am 17. April 2013 (englisch): „"Twin 400 lb-thrust XR-4A3 engines aboard the EZ-Rocket" (with in-flight photograph) ... "Another engine that we have developed in parallel is the XR-4K14, ... a 1,500 lb thrust regeneratively cooled LOX and pump-fed kerosene system ... used as the Rocket Racer aircraft's main engine."“
Allison Gatlin: XCOR performance tested. Antelope Valley Press, 11. Juli 2008, archiviert vom Original (nicht mehr online verfügbar) am 15. Juli 2009; abgerufen am 17. April 2013.
Products Overview. XCOR Aerospace, archiviert vom Original (nicht mehr online verfügbar) am 25. November 2010; abgerufen am 17. April 2013 (englisch): „"Twin 400 lb-thrust XR-4A3 engines aboard the EZ-Rocket" (with in-flight photograph) ... "Another engine that we have developed in parallel is the XR-4K14, ... a 1,500 lb thrust regeneratively cooled LOX and pump-fed kerosene system ... used as the Rocket Racer aircraft's main engine."“
Allison Gatlin: XCOR performance tested. Antelope Valley Press, 11. Juli 2008, archiviert vom Original (nicht mehr online verfügbar) am 15. Juli 2009; abgerufen am 17. April 2013.
Countdown has begun for SXC (Memento vom 27. Dezember 2014 im Internet Archive) „Early next year, we will make the first sub-orbital flight, after which the final development will speed up tremendously. According to our schedule, we will be ready for commercial take-off by the end of 2013“