- Wellenzohn, S.; Proyer, R.T.; Ruch, W.
- Humor-Based Online Positive Psychology Interventions: A Randomized Placebo-Controlled Long-Term Trial
- The Journal of Positive Psychology, 2016, Vol. 11, 584 - 594
- English (Australia, Canada, UK, USA)
Eligible for inclusion in findings archive
- No, no valid measure of happiness used.