- Proyer, R.T.; Gander, F.; Wellenzohn, S.
- Positive Psychology Interventions in People Aged 50-79 Years: Long-Term Effects of Placebo-Controlled Online Interventions on Well-Being and Depression
- Aging & Mental Health, 2014, Vol. 18, 997 - 1005
- English (Australia, Canada, UK, USA)
Eligible for inclusion in findings archive
- No, no valid measure of happiness used.