Crow, C. (1937). Four hundred million customers. H.Hamilton.
Cita Chicago (17th ed.)Crow, Carl. Four Hundred Million Customers. London: H.Hamilton, 1937.
Cita MLA (8th ed.)Crow, Carl. Four Hundred Million Customers. H.Hamilton, 1937.
Atenció: Aquestes cites poden no estar 100% correctes.