APA (7th ed.) Citation

Janson, M., & Opitz, H. (2013). World guide to libraries 2013 (27th ed.). Walter de Gruyter.

Chicago Style (17th ed.) Citation

Janson, Marlies, and Helmut Opitz. World Guide to Libraries 2013. 27th ed. Berlin Boston: Walter de Gruyter, 2013.

MLA (9th ed.) Citation

Janson, Marlies, and Helmut Opitz. World Guide to Libraries 2013. 27th ed. Walter de Gruyter, 2013.