Stone Douglas, Heen, S., & Patton Bruce. (1999). Difficult conversations: How to discuss what matters most. Penguin Books.
Citazione stile Chigago Style (17a edizione)Stone Douglas, Sheila Heen, e Patton Bruce. Difficult Conversations: How to Discuss What Matters Most. New York: Penguin Books, 1999.
Citatione MLA (9a ed.)Stone Douglas, et al. Difficult Conversations: How to Discuss What Matters Most. Penguin Books, 1999.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.