Thorstein Veblen (2016). “THE THEORY OF THE LEISURE CLASS: An Economic Study of American Institutions and a Social Critique of Conspicuous Consumption: Development of Institutions That Shape Society and Influence the Livelihood of Citizens: Based on Sociological & Economical Theories of Charles Darwin, Karl Marx, Adam Smith and Herbert Spencer”, p.68, e-artnow
Thorstein Veblen (2016). “BUSINESS & ECONOMICS Premium Collection: 25+ Titles in One Volume: The Theory of Business Enterprise, The Higher Learning in America, The Vested Interests and the Common Man, On the Nature of Capital…: The Theory of the Leisure Class, The Beginning of Ownership, The Preconceptions of Economic Science, The Industrial System and the Captains of Industry, The Socialist Economics of Karl Marx…”, p.69, e-artnow
William Batchelder Greene (1873). “A Letter to the Rev. Henry W. Foote, Minister of King's Chapel, in Vindication of the Poorer Class of the Boston Working-women”, p.6