HOYLE, Craig. RIAT: Firebird makes European debut as Northrop names buyers. Flight Global [online]. DVV Media Group, 2019-07-21 [cit. 2023-01-09]. Dostupné online. (anglicky)
MARTIN, Tim. Northrop Grumman confirms suspension of Firebird production | Shephard [online]. 2022-04-19 [cit. 2023-01-12]. Dostupné online. (anglicky)
suasnews.com
Grand Sky among first in the world to purchase the Northrop Grumman Firebird [online]. suasnews, 2019-07-19 [cit. 2023-01-06]. Dostupné online. (anglicky)
web.archive.org
SHACHTMAN, Noah. Famed Spaceship Maker Gives Spy Drones a Try [online]. wired, 2011-05-09 [cit. 2023-01-12]. Dostupné v archivu pořízeném z originálu. (anglicky)