David, A., Weisz, B., Peebles, D., Roubliova, X., Perocheau, D., Themis, M., Cook, T., Coutelle, C., Deprest, J., & Rodeck, C. (2004). Ultrasound guided placement of an occlusive balloon in the trachea of fetal sheep. American Journal of Obstetrics and Gynecology, 191(6), S166. https://doi.org/10.1016/j.ajog.2004.10.491 (Original work published 2004)