Citazione Stile APA (7a Edizione)

Willis, D. (1998). Collins COBUILD Student's Grammar: Classroom Edition (Classroom ed.). HarperCollins Publishers.

Citazione stile Chigago Style (17a edizione)

Willis, Dave. Collins COBUILD Student's Grammar: Classroom Edition. Classroom ed. London: HarperCollins Publishers, 1998.

Citatione MLA (9a ed.)

Willis, Dave. Collins COBUILD Student's Grammar: Classroom Edition. Classroom ed. HarperCollins Publishers, 1998.