R. Cotterill

Amniotic fluid embolus. A report of two cases resulting in maternal survival.

T. Benedetti, E. Dashow, C. Kovanda, 1989, The Journal of reproductive medicine.

A reevaluation of placental grading and its clinical significance.

K. Hopper, M. D. Williams, N. Ghaed, 1984, Journal of ultrasound in medicine.