Cita APA (7th ed.)

Ritterskamp, J. J. (1987). Purchasing manager's desk book of purchasing law. Prentice-Hall.

Cita Chicago (17th ed.)

Ritterskamp, James J. Purchasing Manager's Desk Book of Purchasing Law. Englewood Cliffs, N.J: Prentice-Hall, 1987.

Cita MLA (9th ed.)

Ritterskamp, James J. Purchasing Manager's Desk Book of Purchasing Law. Prentice-Hall, 1987.