Benson , L. et al. 1987. Optimal Discrimination of Mild Hyperparathyroidism with Total Serum Calcium, Ionized Calcium and Parathyroid Hormone Measurements. Upsala Journal of Medical Sciences. 92, 2 (Sept. 1987), 147–176. DOI:https://doi.org/10.3109/03009738709178686.