Thomas HODGSKIN (1832). “The Natural and Artificial Right of Property Contrasted. A Series of Letters Addressed, Without Permission, to H. Brougham, Esq., ... by the Author of “Labour Defended Against the Claims of Capital.” [T. Hodgskin. Each Letter Subscribed, “Labourer.”]”, p.24
"Getting from A to Z: Why Animal Activists Should Support Incremental Reforms to Help Animals" by Bruce Friedrich, www.huffingtonpost.com. February 21, 2011.