Comparative study of family functioning, family health, and social support received from nurses among Danish, Icelandic, and Iranian patients with heart failure and their family members. Icelandic title: Samanburðarrannsókn á starfsemi fjölskyldunnar, fjölskylduheilbrigði og félagsleg stuðningi hjúkrunarfræðinga meðal dansrka, íslenskra og Íranskra sjúklinga með hjartabilun og fjölskyldna þeirra.