Citazione Stile APA (7a Edizione)

(1968). Steps to spoken english: A graded course for spanish-speaking. Longman.

Citazione stile Chigago Style (17a edizione)

Steps to Spoken English: A Graded Course for Spanish-speaking. London: Longman, 1968.

Citatione MLA (9a ed.)

Steps to Spoken English: A Graded Course for Spanish-speaking. Longman, 1968.