A low-intensity internet-based intervention focused on the promotion of positive affect for the treatment of depression in Spanish primary care: Secondary analysis of a randomized controlled trial - Vara M.D.; Mira A.; Miragall M.; García-Palacios A.; Botella C.; Gili M.; Riera-Serra P.; García-Campayo J.; Mayoral-Cleries F.; Baños R.M. (International Journal of Environmental Research and Public Health, 2020)