1. Webster’s Ninth New Collegiate Dictionary. Springfield, Massachusetts: Miriam-Webster Inc., 1990.
2. Concise Oxford American Dictionary. New York, New York: Oxford University Press, 2006.
3. Clark RP. Writing Tools: 50 Essential Strategies for Every Writer. New York, New York: Little, Brown and Company, 2006.
4. Clark RP. The Glamour of Grammar. A guide to the magic and mystery of practical English. New York, New York: Little, Brown and Company, 2010.
5. Garner BA. Garner's Modern American Usage. New York, New York: Oxford University Press, 2009.