Early prediction of hypocalcemia after thyroidectomy using parathyroid hormone: an analysis of pooled individual patient data from nine observational studies. - Noordzij JP; Lee SL; Bernet VJ; Payne RJ; Cohen SM; McLeod IK; Hier MP; Black MJ; Kerr PD; Richards ML; Lo CY; Raffaelli M; et al. (Journal of the American College of Surgeons, 2007)