APA (7th ed.) Citation

English, A. K., English, L. M., Boyd, F. A., & Numrich, C. (1998). Northstar: Focus on reading and writing : high intermediate. Longman.

Chicago Style (17th ed.) Citation

English, Andrew K., Laura Monahon English, Frances Armstrong Boyd, and Carol Numrich. Northstar: Focus on Reading and Writing : High Intermediate. New York: Longman, 1998.

MLA (9th ed.) Citation

English, Andrew K., et al. Northstar: Focus on Reading and Writing : High Intermediate. Longman, 1998.