title: Bibliography of biomedical ultrasound from 1 January 1971, No. 20.
mesh_terms: D000005:Abdomen / Q000033:anatomy & histology; D001634:Bibliographies as Topic; D002319:Cardiovascular System / Q000033:anatomy & histology; D004301:Doppler Effect; D005260:Female; D005333:Fetus / Q000033:anatomy & histology; D005836:Genitalia, Female / Q000033:anatomy & histology; D049673:History, 20th Century; D006801:Humans; D014465:Ultrasonics / Q000295:instrumentation; D014463:Ultrasonography