Predicting risk for venous thromboembolism with bariatric surgery: results from the Michigan Bariatric Surgery Collaborative - Finks, JF; English, WJ; Carlin, AM; Krause, KR; Share, DA; Banerjee, M; Birkmeyer, JD; Birkmeyer, NJ; Michigan Bariatric Surgery Collaborative; Center for Healthcare Outcomes and Policy (Ann Surg, 2012)