Lucas, R. W. (2009). Customer Service (4th.). McGraw Hill.
Cita Chicago (17th ed.)Lucas, Robert W. Customer Service. 4th. New York: McGraw Hill, 2009.
Cita MLA (9th ed.)Lucas, Robert W. Customer Service. 4th. McGraw Hill, 2009.
Atenció: Aquestes cites poden no estar 100% correctes.