1. AIUM. AIUM practice guideline for the performance of obstetric ultrasound examinations. 〈http://www.aium.org/resources/guidelines/obstetric.pdf〉; 2007 [cited October 29, 2012].
2. ARDMS. SPI requirement and general prerequisites. 〈http://www.ardms.org/files/downloads/Prerequisite_Chart.pdf〉; 2012 [cited October 29, 2012].
3. EBCOG. Postgraduate training and assessment in obstetrics and gynaecology. Log Book. 〈http://www.ebcog.org〉; 2005 [cited October 29, 2012].
4. EFSUMB. Minimum training requirements for the practice of medical ultrasound in Europe. 〈http://www.efsumb.org/guidelines/2009-04-14apx4.pdf〉; 2005 [cited October 29, 2012].
5. Update on proposed minimum standards for ultrasound training for residents in Ob/Gyn;Ultrasound Obstet Gynecol,1996