Mackay, Charles; Ramsay, Allan; May, G. (1888). "Black-mail". A dictionary of Lowland Scotch, with an introductory chapter on the poetry, humour, and literary history of the Scottish language and an appendix of Scottish proverbs. London: Whittaker. pp. 10–12.
Lindgren (1984), p. 670: "Most crimes do not need theories to explain why the behavior is criminal. The wrongdoing is self-evident. But blackmail is unique among major crimes: no one has yet figured out why it ought to be illegal." Lindgren, James (1984). "Unraveling the Paradox of Blackmail". Columbia Law Review. 84 (3): 670–717. doi:10.2307/1122502. JSTOR1122502.
Walter Block, N. Stephan Kinsella and Hans-Hermann Hoppe (July 2000), "The Second Paradox of Blackmail", Business Ethics Quarterly, 10 (3): 593–622, doi:10.2307/3857894, JSTOR3857894, S2CID5684396
Lindgren (1984), p. 670: "Most crimes do not need theories to explain why the behavior is criminal. The wrongdoing is self-evident. But blackmail is unique among major crimes: no one has yet figured out why it ought to be illegal." Lindgren, James (1984). "Unraveling the Paradox of Blackmail". Columbia Law Review. 84 (3): 670–717. doi:10.2307/1122502. JSTOR1122502.
Walter Block, N. Stephan Kinsella and Hans-Hermann Hoppe (July 2000), "The Second Paradox of Blackmail", Business Ethics Quarterly, 10 (3): 593–622, doi:10.2307/3857894, JSTOR3857894, S2CID5684396
Walter Block, N. Stephan Kinsella and Hans-Hermann Hoppe (July 2000), "The Second Paradox of Blackmail", Business Ethics Quarterly, 10 (3): 593–622, doi:10.2307/3857894, JSTOR3857894, S2CID5684396