APA (7th ed.) Citation

Princeton Language Institute, (Ed). (1995). 21st century guide to improving your writing. Dell Pub.

Chicago Style (17th ed.) Citation

Princeton Language Institute, (Ed). 21st Century Guide to Improving Your Writing. New York: Dell Pub, 1995.

MLA (9th ed.) Citation

Princeton Language Institute, (Ed). 21st Century Guide to Improving Your Writing. Dell Pub, 1995.