Ford JB, Shand AW, Roberts CL. Aust N Z J Obstet Gynaecol. 2013 feb;53(1):90-3. doi: 10.1111/ajo.12019. Epub 2012 dic 4.
Clinical and Population Perinatal Health Research, Kolling Institute of Medical Research, Royal North Shore Hospital, University of Sydney, Sydney, NSW, Australia.