Comparison of the Carpentier–Edwards Perimount and St. Jude Medical Epic bioprostheses for aortic valve replacement--a retrospective echocardiographic short-term study - Goetzenich, A; Langebartels, G; Christiansen, S; Hatam, N; Autschbach, R; Dohmen, G (J Card Surg, 2009)