APA (7th ed.) Citation

Larsen-Freeman, D., & Long, M. H. (1991). An introduction to second language acquisition research. Longman.

Chicago Style (17th ed.) Citation

Larsen-Freeman, Diane, and Michael H. Long. An Introduction to Second Language Acquisition Research. London: Longman, 1991.

MLA (9th ed.) Citation

Larsen-Freeman, Diane, and Michael H. Long. An Introduction to Second Language Acquisition Research. Longman, 1991.