Alone in the Crowd: The Structure and Spread of Loneliness in a Large Social Network.

John T. Cacioppo, James H. Fowler, and Nicholas A. Christakis.
J Pers Soc Psychol. Author manuscript; available in PMC Jan 1, 2010.
Published in final edited form as:
Journal of Personality and Social Psychology, 2009, Vol. 97, No. 6, 977–991.
doi: 10.1037/a0016076