APA
Fogel R. W., Engerman S. L., . (1974). Time on the cross: The economics of American negro slavery. Boston: LittleBrown Com.
Chicago
Fogel R W, Engerman S L, . 1974. Time on the cross: The economics of American negro slavery. Boston: LittleBrown Com.
Harvard
Fogel R. W., Engerman S. L., . (1974). Time on the cross: The economics of American negro slavery. Boston: LittleBrown Com.
MLA
Fogel R W, Engerman S L, . Time on the cross: The economics of American negro slavery. Boston: LittleBrown Com. 1974.