Cita APA (7th ed.)
Irvine, D. E. G., & Seshold, M. Errors in Postage Stamp Design.
Cita Chicago (17th ed.)
Irvine, David E. G., i Maxwell Seshold. Errors in Postage Stamp Design.
Cita MLA (9th ed.)
Irvine, David E. G., i Maxwell Seshold. Errors in Postage Stamp Design.
Atenció: Aquestes cites poden no estar 100% correctes.