APA (7th ed.) Citation

Philip Lief Group, Princeton Language Institute, & Laskowski, L. (2001). 10 days to more confident public speaking. Warner Books.

Chicago Style (17th ed.) Citation

Philip Lief Group, Princeton Language Institute, and Lenny Laskowski. 10 Days to More Confident Public Speaking. New York: Warner Books, 2001.

MLA (9th ed.) Citation

Philip Lief Group, et al. 10 Days to More Confident Public Speaking. Warner Books, 2001.