Ruokonen A, Hyltoft-Petersen P, Blaabjerg O. External Quality Assurance Model for Improvement of Specificity and Assuracy of Serum Hormone Determinations in the Nordic Countries. ujms [Internet]. 1990Sep.1 [cited 2024May4];95(3):257-8. Available from: https://ujms.net/index.php/ujms/article/view/6780