1. Clinical bulletin no. 1: Limited obstetrical ultrasound in the third trimester,1996
2. Position statement: Midwives performance of ultrasound in clinical practice,2010
3. Practice bulletin 101: Ultrasonography in pregnancy,2009
4. AIUM practice guideline for the performance of obstetric ultrasound examinations,2007
5. Clinical competencies and education guide: Limited ultrasound examinations in obstetric and gynecologic/infertility settings,1993