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.99
Mark Twain (2014). “Mark Twain on Common Sense: Timeless Advice and Words of Wisdom from America's Most-Revered Humorist”, p.6, Skyhorse Publishing, Inc.