Crosby, P. B. (1979). Quality is free: The art of making quality certain. McGraw-Hill.
Cita Chicago (17th ed.)Crosby, Philip B. Quality Is Free: The Art of Making Quality Certain. New York: McGraw-Hill, 1979.
Cita MLA (9th ed.)Crosby, Philip B. Quality Is Free: The Art of Making Quality Certain. McGraw-Hill, 1979.
Atenció: Aquestes cites poden no estar 100% correctes.