Hartz, Ingeborg, Jørgen G. Bramness, and Svetlana Skurtveit. 2011. “Prescription of Antidepressants to Patients on Opioid Maintenance Therapy – a Pharmacoepidemiological Study”. Norsk Epidemiologi 21 (1). https://doi.org/10.5324/nje.v21i1.1429.