Influence of iodine on the reference interval of TSH and the optimal interval of TSH: results of a follow-up study in areas with different iodine intakes - Guan, H; Shan, Z; Teng, X; Li, Y; Teng, D; Jin, Y; Yu, X; Fan, C; Chong, W; Yang, F; Dai, H; Yu, Y; Li, J; Chen, Y; Zhao, D; Shi, X; Hu, F; Mao, J; Gu, X; Yang, R; Chen, W; Tong, Y; Wang, W; Gao, T; Li, C; Teng, W (Clin Endocrinol (Oxf), 2008)