APA (7th ed.) Citation

Conrad, S., & Biber, D. (2001). Variation in English: Multi-dimensional studies. Longman.

Chicago Style (17th ed.) Citation

Conrad, Susan, and Douglas Biber. Variation in English: Multi-dimensional Studies. Harlow, Eng: Longman, 2001.

MLA (9th ed.) Citation

Conrad, Susan, and Douglas Biber. Variation in English: Multi-dimensional Studies. Longman, 2001.