Preoperative risk stratification for thoracic surgery using the American College of Surgeons National Surgical Quality Improvement Program data set: functional status predicts morbidity and mortality - Tsiouris, Athanasios; Horst, Harriette M.; Paone, Gaetano; Hodari, Arielle; Eichenhorn, Michael; Rubinfeld, Ilan (Journal of Surgical Research, 2012)