"Morgan Freeman Talks OBLIVION, Working with Tom Cruise, Being Drawn to Sci-Fi and Technology, Shooting a Dual .50 Caliber Machine Gun and More". collider.com. April 16, 2013.
James Boswell, Samuel Johnson (1824). “The Life of Samuel Johnson, LL. D., Comprehending an Account of His Studies, and Numerous Works, in Chronological Order: A Series of His Epistolary Correspondence and Conversations with Many Eminent Persons; and Various Original Pieces of His Composition, Never Before Published; the Whole Exhibiting a View of Literature and Literary Men in Great Britain, for Near Half a Century During which He Flourished”, p.209