The Concept of “Direct Mechanical Ventricular Assistance” in the Treatment of Left-Ventricular Failure - Part 1: Idea, Development and Construction of an Implantable Multi-Chamber Pump System Partially Surrounding the Heart - Feindt, P; Gams, E; Kazi, A; Straub, U; Paul, V; Priebe, J; Meyer, U; Gersonde, K (The Thoracic and Cardiovascular Surgeon, 1995)