Evaluation of heroin-assisted treatment in Norway: protocol for a mixed methods study. - Myklebust, Lars Henrik; Eide, Desiree; Arnevik, Espen A.; Dadras, Omid; De Pirro, Silvana; Ellefsen, Rune; Fadnes, Lars T.; Hesse, Morten; Kvamme, Timo L.; Melis, Francesca; Oldervoll, Ann; Thylstrup, Birgitte; et al. (BMC Health Services Research, 2024)