Assessment of Different Preservation and Storage Conditions on Aortic Valves: Introduction of a Quantitative Measuring Method of the Integrity of Endothelial Cells - Kümper, A; Kümper, C; Kraatz, E G; Wottge, H U; Dreyer, W; Yankah, A C; Bernhard, A (The Thoracic and Cardiovascular Surgeon, 1989)