[1] Univ Agder, Kristiansand, Norway
[2] Sorlandet Hosp, Kristiansand, Norway
[3] Univ Agder, Grimstad, Norway
[4] Martina Hansens Hosp, Baerum, Norway
[5] Martina Hansens Hosp, Kristiansand, Norway
[6] Norwegian Univ Sci & Technol, Kristiansand, Norway