APA (7th ed.) Citation

Janson, M., & Opitz, H. (2007). World guide to libraries (21st ed.). K. G. Saur.

Chicago Style (17th ed.) Citation

Janson, Marlies, and Helmut Opitz. World Guide to Libraries. 21st ed. München: K. G. Saur, 2007.

MLA (9th ed.) Citation

Janson, Marlies, and Helmut Opitz. World Guide to Libraries. 21st ed. K. G. Saur, 2007.

Warning: These citations may not always be 100% accurate.