APA (7th ed.) Citation

Bartz, B., Lochar, R., & Opitz, H. (1990). World guide to special libraries (2nd ed.). K.G. Sauer.

Chicago Style (17th ed.) Citation

Bartz, Bettina, Ruth Lochar, and Helmut Opitz. World Guide to Special Libraries. 2nd ed. München ; New York: K.G. Sauer, 1990.

MLA (9th ed.) Citation

Bartz, Bettina, et al. World Guide to Special Libraries. 2nd ed. K.G. Sauer, 1990.