First uses of HAART 300 rings for aortic valve repair in Poland – 4 case studies - Juściński, Jacek H.; Koprowski, Andrzej; Kołaczkowska, Magdalena; Kowalik, Maciej M.; Rogowski, Jan A.; Rankin, James S. (Kardiochirurgia i Torakochirurgia Polska/Polish Journal of Thoracic and Cardiovascular Surgery, 2018)