Mazza, V.; Falcinelli, C.; Paganelli, S.; Contu, G.; Mantuano, S. M.; Battafarano, S. D.; Forabosco, A.; Volpe, A. (2001). "Sonographic early fetal gender assignment: a longitudinal study in pregnancies after in vitro fertilization". Ultrasound in Obstetrics & Gynecology. 17 (6): 513–516. doi:10.1046/j.1469-0705.2001.00421.x. PMID11422974.
Mazza, V.; Falcinelli, C.; Paganelli, S.; Contu, G.; Mantuano, S. M.; Battafarano, S. D.; Forabosco, A.; Volpe, A. (2001). "Sonographic early fetal gender assignment: a longitudinal study in pregnancies after in vitro fertilization". Ultrasound in Obstetrics & Gynecology. 17 (6): 513–516. doi:10.1046/j.1469-0705.2001.00421.x. PMID11422974.