Feldmann, C. P. (1994). International invention guide. IFIA.
Cita Chicago (17th ed.)Feldmann, Clarence P. International Invention Guide. Geneva: IFIA, 1994.
Cita MLA (9th ed.)Feldmann, Clarence P. International Invention Guide. IFIA, 1994.
Atenció: Aquestes cites poden no estar 100% correctes.