Embryonic Length,Crown-Rump Length and Fetal Heart Activity in Early Human Pregnancy Determination by Transvaginal Ultrasound

Robinson HP Fleming JEE 1975, A critical evaluation of sonar “crown-rump length” measurements. British Journal of Obstetrics and Gynaecology, 85:702–710.

Science Citation Index. Number of citations between 1975 and August 1992.

Fetal measurements working party report, British Medical Ultrasound Society, 1990, Clinical applications of ultrasonic fetal measurements, Publ: British Institute of Radiology, London.

Schats R Jansen CAM Wladimiroff JW 1990a, Embryonic heart activity:appearance and development in early human pregnancy. British Journal of Obstetrics and Gynaecology, 97:989–994.

Schats R Jansen CAM Wladimiroff JW 1990b, Asynchronous appearance of embryonic cardiac activity in multiple pregnancies following in-vitro fertilisation. Unltrasound in Medicine and Biology, 16:728–730.

Schats R Van Os HC Jansen CAM Wladimiroff JW 1991, The crown-rump length in early human pregnancy:a reappraisal. British Journal of Obstetrics and Gynaecology, 98:460–462.

RMI Tissue mimicking Ultrasound Phantom model 414 A, Radiation Measurement Inc, po box 327, Middleton, WI 53562 USA.

Van Os HC Hout J. in 't Hermans J Jansen CAM 1993. A reappraisal of embryonic and fetal CRL measurements:the transvaginal approach. Submitted for publication.

Laird NM Ware JH 1982, Random effects models for longitudinal data. Biometrics, 38 963–974.