APA (7th ed.) Citation

Tittel, E. (1997). ISDN clearly explained (2nd ed.). AP Professional.

Chicago Style (17th ed.) Citation

Tittel, Ed. ISDN Clearly Explained. 2nd ed. Boston, Mass: AP Professional, 1997.

MLA (9th ed.) Citation

Tittel, Ed. ISDN Clearly Explained. 2nd ed. AP Professional, 1997.