APA (7th ed.) Citation

English Language Services, Inc. (Los Angeles, Calif.). English 900: A basic course. English Language Services.

Chicago Style (17th ed.) Citation

English Language Services, Inc. (Los Angeles, Calif.). English 900: A Basic Course. Los Angeles: English Language Services.

MLA (9th ed.) Citation

English Language Services, Inc. (Los Angeles, Calif.). English 900: A Basic Course. English Language Services.

Warning: These citations may not always be 100% accurate.