APA (7th ed.) Citation

Janson, M., & Opitz, H. (2015). World guide to libraries: 2015/2016 (30th ed.). Walter de Gruyter.

Chicago Style (17th ed.) Citation

Janson, Marlies, and Helmut Opitz. World Guide to Libraries: 2015/2016. 30th ed. Berlin München Boston: Walter de Gruyter, 2015.

MLA (9th ed.) Citation

Janson, Marlies, and Helmut Opitz. World Guide to Libraries: 2015/2016. 30th ed. Walter de Gruyter, 2015.