NOWICKI, A., J. M. REID, and M. P. SPENCER. 2015. “Ultrasonic Doppler MTI System for Evaluation of Aortocoronary Bypass Graft Patency”. Archives of Acoustics 9 (1-2): 243-50. https://acoustics3.ippt.pan.pl/index.php/aa/article/view/3220.