APA (7th ed.) Citation

ProQuest (Firm), Kortman, B., & Lunkenheimer, K. (2012). The Mouton world atlas of variation in English. DeGruyter Mouton.

Chicago Style (17th ed.) Citation

ProQuest (Firm), Bernd Kortman, and Kerstin Lunkenheimer. The Mouton World Atlas of Variation in English. Berlin: DeGruyter Mouton, 2012.

MLA (9th ed.) Citation

ProQuest (Firm), et al. The Mouton World Atlas of Variation in English. DeGruyter Mouton, 2012.