APA (7th ed.) Citation

Duffy, T. M., Palmer, J. E., & Mehlenbacher, B. (1992). Online help: Design and evaluation. Ablex Pub..

Chicago Style (17th ed.) Citation

Duffy, Thomas M., James E. Palmer, and Brad Mehlenbacher. Online Help: Design and Evaluation. Norwood, N.J.: Ablex Pub., 1992.

MLA (9th ed.) Citation

Duffy, Thomas M., et al. Online Help: Design and Evaluation. Ablex Pub., 1992.