Cita APA (7th ed.)

Frenzel, L. E. (1981). Digital counter handbook. H.W. Sams.

Cita Chicago (17th ed.)

Frenzel, Louis E. Digital Counter Handbook. Indianapolis, Ind.: H.W. Sams, 1981.

Cita MLA (8th ed.)

Frenzel, Louis E. Digital Counter Handbook. H.W. Sams, 1981.