APA (7th ed.) Citation

Helal, A. H., & Weiss, J. W. (1993). Opportunity 2000: Understanding and serving users in an electronic library. Universitatsbibliothek Essen.

Chicago Style (17th ed.) Citation

Helal, Ahmed H., and Joachim W. Weiss. Opportunity 2000: Understanding and Serving Users in an Electronic Library. Essen: Universitatsbibliothek Essen, 1993.

MLA (8th ed.) Citation

Helal, Ahmed H., and Joachim W. Weiss. Opportunity 2000: Understanding and Serving Users in an Electronic Library. Universitatsbibliothek Essen, 1993.