(1969). Steps to spoken english: A graded course for spanish-speaking students. Longman.
Chicagoスタイル(17版)引用形式Steps to Spoken English: A Graded Course for Spanish-speaking Students. London: Longman, 1969.
MLA(9版)引用形式Steps to Spoken English: A Graded Course for Spanish-speaking Students. Longman, 1969.
警告: この引用は必ずしも正確ではありません.