Baulies S، Maiz N، Muñoz A، Torrents M، Echevarría M، Serra B (2007). "Prenatal ultrasound diagnosis of vasa praevia and analysis of risk factors". Prenatal Diagnosis. ج. 27 ع. 7: 595–599. DOI:10.1002/pd.1753. PMID:17497747. S2CID:37634607.
Vintzileos A، Ananth C، Smulian J (2015). "Using ultrasound in the clinical management of placental implantation abnormalities". American Journal of Obstetrics and Gynecology. ج. 213 ع. 4: S70–S77. DOI:10.1016/j.ajog.2015.05.059. PMID:26428505.
Baulies S، Maiz N، Muñoz A، Torrents M، Echevarría M، Serra B (2007). "Prenatal ultrasound diagnosis of vasa praevia and analysis of risk factors". Prenatal Diagnosis. ج. 27 ع. 7: 595–599. DOI:10.1002/pd.1753. PMID:17497747. S2CID:37634607.
Vintzileos A، Ananth C، Smulian J (2015). "Using ultrasound in the clinical management of placental implantation abnormalities". American Journal of Obstetrics and Gynecology. ج. 213 ع. 4: S70–S77. DOI:10.1016/j.ajog.2015.05.059. PMID:26428505.