Cita APA (7th ed.)

Erk, M. H. v., & Onstee, H. G. (1974). Digital instrument cource. Philips.

Cita Chicago (17th ed.)

Erk, M. H van, i H. G. Onstee. Digital Instrument Cource. Eindhoven: Philips, 1974.

Cita MLA (9th ed.)

Erk, M. H van, i H. G. Onstee. Digital Instrument Cource. Philips, 1974.