DUFF, J. M. (1983). Problems in industrial technical illustration. Brooks/ Cole engineering division.
Cita Chicago (17th ed.)DUFF, John M. Problems in Industrial Technical Illustration. California: Brooks/ Cole engineering division, 1983.
Cita MLA (9th ed.)DUFF, John M. Problems in Industrial Technical Illustration. Brooks/ Cole engineering division, 1983.
Atenció: Aquestes cites poden no estar 100% correctes.