APA (7th ed.) Citation

Willis, J. R., & Willis, D. (1988). Collins Cobuild English course: Student's book 1. Collins.

Chicago Style (17th ed.) Citation

Willis, Jane R., and Dave Willis. Collins Cobuild English Course: Student's Book 1. London: Collins, 1988.

MLA (8th ed.) Citation

Willis, Jane R., and Dave Willis. Collins Cobuild English Course: Student's Book 1. Collins, 1988.