Citazione Stile APA (7a Edizione)

Walker, E., & Elsworth, S. (1994). Grammar practice for intermediate students (Rev. ed.). Longman.

Citazione stile Chigago Style (17a edizione)

Walker, Elaine, e Steve Elsworth. Grammar Practice for Intermediate Students. Rev. ed. Essex: Longman, 1994.

Citatione MLA (9a ed.)

Walker, Elaine, e Steve Elsworth. Grammar Practice for Intermediate Students. Rev. ed. Longman, 1994.