APA (7th ed.) Citation

Coover, E. R. (1989). Tutorial: Digital private branch exchanges <PBXs>. IEEE Computer Soc. Press.

Chicago Style (17th ed.) Citation

Coover, Edwin R. Tutorial: Digital Private Branch Exchanges <PBXs>. Washington, DC: IEEE Computer Soc. Press, 1989.

MLA (9th ed.) Citation

Coover, Edwin R. Tutorial: Digital Private Branch Exchanges <PBXs>. IEEE Computer Soc. Press, 1989.