Cita APA (7th ed.)
Schuller, R. H. (1980). The peak to peek principle. Doubleday & Co.
Cita Chicago (17th ed.)
Schuller, Robert H. The Peak to Peek Principle. Garden City, New York: Doubleday & Co, 1980.
Cita MLA (9th ed.)
Schuller, Robert H. The Peak to Peek Principle. Doubleday & Co, 1980.
Atenció: Aquestes cites poden no estar 100% correctes.