APA (7th ed.) Zitazioa

(1969). Steps to spoken english: A graded course for spanish-speaking students. Longman.

Chicago Style (17th ed.) Zitazioa

Steps to Spoken English: A Graded Course for Spanish-speaking Students. London: Longman, 1969.

MLA (9th ed.) Zitazioa

Steps to Spoken English: A Graded Course for Spanish-speaking Students. Longman, 1969.