1. Australasian Society for Ultrasound in Medicine (ASUM) Policies and Statements, D2 - Guidelines for the Mid Trimester Obstetric Scan http://www.asum.com.au/newsite/files/documents/policies/PS/02_policy.pdf
2. Australasian Society for Ultrasound in Medicine (ASUM) Policies and Statements, D7 - Statement on Normal Ultrasonic Fetal Measurements http://www.asum.com.au/newsite/files/documents/policies/PS/07_policy.pdf
3. The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG) RANZCOG College Statement C-Obs 35 Prenatal screening for fetal abnormalities http://www.ranzcog.edu.au/the-ranzcog/policies-and-guidelines/college-statements.html
4. A pictorial guide for the second trimester ultrasound;Bethune;Australas J Ultrasound Med,2013
5. Fetal biometry: clinical, pathological, and technical considerations;Degani;Obstet Gynecol Surv,2001