De La Calle, M. Delgado, J.L. Verlohren, S. Escudero, A.I. Bartha, J.L. Campillos, J.M. Aguarón De La Cruz, A. Chantraine, F. García Hernández, J.Á. Herraiz, I. Llurba, E. Kurka, H. Guo, G. Sillman, J. Hund, M. Perales Marín, A. Gestational Age-Specific Reference Ranges for the sFlt-1/PlGF Immunoassay Ratio in Twin Pregnancies Fetal diagn. ther. 10.1159/000514378 2021 2021