APA (7th ed.) Citation

Stone, D., Patton, B., & Heen, S. (1999). Difficult conversations: How to discuss what matters most. Viking.

Chicago Style (17th ed.) Citation

Stone, Douglas, Bruce Patton, and Sheila Heen. Difficult Conversations: How to Discuss What Matters Most. New York, N.Y.: Viking, 1999.

MLA (8th ed.) Citation

Stone, Douglas, et al. Difficult Conversations: How to Discuss What Matters Most. Viking, 1999.