Cita APA (7th ed.)

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

Cita Chicago (17th ed.)

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

Cita MLA (9th ed.)

The Princeton Language Institute, et al. 10 Days to More Confident Public Speaking. Warner Books, 2001.