Oka RK, De Marco T, Haskell WL. Perceptions of physical fitness in patients with heart failure. Progress in Cardiovasc Nursing. 1999; 3(14):97-102. 1999 https://researcherprofiles.org/profile/1330570 Oka RK, De Marco T, Haskell WL. Perceptions of physical fitness in patients with heart failure. Progress in Cardiovasc Nursing