Falk, Volkmar, James I. Fann, Jürg Grünenfelder, and Thomas A. Burdon. 2000. “Endoscopic Doppler for Detecting Vessels in Closed Chest Bypass Grafting”. The Heart Surgery Forum 3 (4):E331-E333. https://journal.hsforum.com/index.php/HSF/article/view/6511.