Fogel, R. W., & Engerman, S. L. (1974). Time on the cross: The economics of American Negro slavery (First edition.). Little, Brown.
Lua i Stíl Chicago (17ú heag.)Fogel, Robert William, agus Stanley L. Engerman. Time on the Cross: The Economics of American Negro Slavery. First edition. Boston: Little, Brown, 1974.
Lua MLA (8ú heag.)Fogel, Robert William, agus Stanley L. Engerman. Time on the Cross: The Economics of American Negro Slavery. First edition. Little, Brown, 1974.
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