title: Survival: proactive roles in a changing environment.
authors: University of Pennsylvania, Philadelphia 19104.
authors: R A
authors: RA
authors: Stevens
mesh_terms: D004465:Economic Competition; D006291:Health Policy / Q000639:trends*; D006740:Hospital Administrators / Q000639:trends*; D012380:Role; D012922:Social Change; D014481:United States