Svebak, S., and H. Halvari. “Sickness Absence Due to Chronic Musculoskeletal Pain: The Exploration of a Predictive Psychological Model Including Negative Moods, Subjective Health and Work Efficacy in an Adult County Population (The HUNT Study)”. Europe’s Journal of Psychology, Vol. 14, no. 2, June 2018, pp. 373-85, doi:10.5964/ejop.v14i2.1470.