Walker E. Elaine & Elsworth S. Steve. (2002). New Grammar Practice for Pre-Intermediate Students with key (3-rd ed.). Longman, 2002.
Citazione stile Chigago Style (17a edizione)Walker E. Elaine e Elsworth S. Steve. New Grammar Practice for Pre-Intermediate Students with Key. 3-rd ed. Longman, 2002, 2002.
Citatione MLA (9a ed.)Walker E. Elaine e Elsworth S. Steve. New Grammar Practice for Pre-Intermediate Students with Key. 3-rd ed. Longman, 2002, 2002.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.