Long-term (9-year) follow-up of patients undergoing retrograde nontransseptal balloon mitral valvuloplasty - Stefanadis, CC; Stratos, CG; Lambrou, SG; Bahl, VK; Cokkinos, D.V.; Voudris, VA; Foussas, SG; Tsioufis, CP; Toutouzas, PK (Journal of the American College of Cardiology, 1998)