Interobserver Variability of the Measurement of Fetal Nasal Bone Length between 11 + 0 and 13 + 6 Gestation Weeks among Experienced and Inexperienced Sonographers - Staboulidou, I; Wüstemann, M; Vaske, B; Scharf, A; Hillemanns, P; Schmidt, P (Ultraschall in der Medizin - European Journal of Ultrasound, 2009)