Funk, W. (1971). SiX weeks to words of power. Pocket Books.
Cita Chicago (17th ed.)Funk, Wilfred. SiX Weeks to Words of Power. New York, Estados Unidos: Pocket Books, 1971.
Cita MLA (9th ed.)Funk, Wilfred. SiX Weeks to Words of Power. Pocket Books, 1971.
Atenció: Aquestes cites poden no estar 100% correctes.