D. M. Holzhey, J. P. Cornely, A. J. Rastan, P. Davierwala, and F. W. Mohr, “Review of a 13-Year Single-Center Experience with Minimally Invasive Direct Coronary Artery Bypass as the Primary Surgical Treatment of Coronary Artery Disease”, HSF, vol. 15, no. 2, pp. E61-E68, Apr. 2012.