Zhang Y, Post WS, Dalal D, Bansal S, Blasco-Colmenares E, Jan De Beur S, Alonso A, Soliman EZ, Whitsel EA, Brugada R, Tomaselli GF, Guallar E. Serum 25-hydroxyvitamin D, calcium, phosphorus, and electrocardiographic QT interval duration: findings from NHANES III and ARIC. J Clin Endocrinol Metab. 2011 Jun; 96(6):1873-82.