Cita APA (7a ed.)

Gras, N. S. B. (1922). An introduction to economic history. Harper.

Cita Chicago Style (17a ed.)

Gras, Norman Scott Brien. An Introduction to Economic History. New York ; London: Harper, 1922.

Cita MLA (8a ed.)

Gras, Norman Scott Brien. An Introduction to Economic History. Harper, 1922.