Penttilä , I. M., M. Ryynänen, E. Hämäläinen, E. Puhakainen, and K. Savolainen. “6.1.3.2 Quality Specifications for S-AFP and S-HCG-β Determinations for Screening of Fetal Abnormalities”. Upsala Journal of Medical Sciences 98, no. 3 (September 1, 1993): 375-380. Accessed March 27, 2026. https://ujms.net/index.php/ujms/article/view/7498.