English Language Services. (1964). The key to English. Collier-Macmillan.
Chicago Style (17th ed.) CitationEnglish Language Services. The Key to English. London: Collier-Macmillan, 1964.
MLA (9th ed.) CitationEnglish Language Services. The Key to English. Collier-Macmillan, 1964.
Warning: These citations may not always be 100% accurate.