Crosby, P. B. (1979). Quality is free: The art of making quality certain. New York: A Mentor Book.
Trích dẫn kiểu ChicagoCrosby, Philip B. Quality Is Free: The Art of Making Quality Certain. New York: A Mentor Book, 1979.
Deismireacht MLACrosby, Philip B. Quality Is Free: The Art of Making Quality Certain. New York: A Mentor Book, 1979.
Rabhadh: D'fhéadfadh nach mbeadh na deismireachtaí seo 100% cruinn i gcónaí.