Thomas Robert Malthus “An Essay on the Principle of Population, Or, a View of Its Past and Present Effects on Human Happiness: With an Inquiry Into Our Prospects Respecting the Future Removal Or Mitigation of the Evils which it Occasions”, Cambridge University Press
"Principles of political economy considered with a view to their practical application". Book by Thomas Malthus, Book II, Chapter I, "On The Progress of Wealth", Section X, p. 414, 1836.
"Principles of political economy considered with a view to their practical application". Book by Thomas Robert Malthus, Book II, Chapter I, "On the Progress of Wealth", Section I, p. 309, 1836.