Replacement of the Aortic Root by Free Implantation of a Stentless Aortic Porcine Bioprosthesis* in a Patient with Aneurysm of the Sinuses of Valsalva - Sievers, H -H; Podszus, G; Lange, P E; Bürsch, J H; Bernhard, A (The Thoracic and Cardiovascular Surgeon, 1985)