NASA GSFC Science and Exploration. 20. März 2019, abgerufen am 21. März 2019 (ab Minute 24:14): „There is a myth that Vulcan is a brand new rocket. That's partially true, but mostly not. Vulcan is derived from the best parts of Atlas and from Delta …“
Twitter-Nachricht vom Eric Berger, 28. November 2018: „… the Vulcan-Centaur Heavy (with an upgraded Centaur second stage) will launch in 2023.“ (englisch)
