1)Dietz HP, et al : Measuring engagement of the fetal head : validity and reproducibility of a new ultrasound technique. Ultrasound Obstet Gynecol 25 : 165-168, 2005
2)Tutscheck B, et al : Comparison between ultrasound parameters and clinical examination to assess fetal head station in labor. Ultrasound Obstet Gynecol 41 : 425-429, 2013
3)Tutschek B, et al : A study of progress of labor using intrapartum translabial ultrasound, assessing head station, direction, and angle of descent. BJOG 118 : 62-69, 2011
4)Bellussi F, et al : The use of intrapartum ultrasound to diagnose malpositions and cephalic malpresentations. Am J Obstet Gynecol 217 : 633-641, 2017
5)Ghi T, et al : ISUOG Practice Guidelines : intrapartum ultrasound. Ultrasound Obstet Gynecol 52 : 128-139, 2018