Powell, Thomas J.; Hill, Elizabeth M.; Warner, Lynn; Yeaton, Willian; Silk, Kenneth R. (2000). "Encouraging People With Mood Disorders to Attend a Self-Help Group". Journal of Applied Social Psychology. 20 (11): 2270–2288. doi:10.1111/j.1559-1816.2000.tb02436.x. ISSN0021-9029.
Powell, Thomas J.; Hill, Elizabeth M.; Warner, Lynn; Yeaton, Willian; Silk, Kenneth R. (2000). "Encouraging People With Mood Disorders to Attend a Self-Help Group". Journal of Applied Social Psychology. 20 (11): 2270–2288. doi:10.1111/j.1559-1816.2000.tb02436.x. ISSN0021-9029.