Geidel, S., Lass, M., & Ostermeyer, J. (2008). Restrictive Mitral Valve Annuloplasty for Chronic Ischemic Mitral Regurgitation: A 5-Year Clinical Experience with the Physio Ring. The Heart Surgery Forum, 11(4), E225-E230. https://doi.org/10.1532/HSF98.20081028