Lockheed Martin RQ-170 Sentinel still in top secrecy - Defence Aviation
The U.S. Air Force's Stealth Drone Could Have a New Mission - War Is Boring
Declassified Docs Offer New Details About A Growing RQ-170 "Wraith" Force
China Large Stealth Drone better than US RQ-170 drone | NextBigFuture.com
Lockheed Martin RQ-170 Sentinel - Wikipedia
Why did the US Air Force's RQ-170 Sentinel stealth reconnaissance drone have a grill covering its engine inlet instead of using an inlet like the B-2 Spirit? - Quora
Opinion: Armed drones are key to future of warfare | CNN
Official: US limits intel value of drones - The San Diego Union-Tribune