title: An ultrasonic imaging and differential measurement system for the study of fetal respiratory movements.
mesh_terms: D000328:Adult; D005318:Fetal Heart / Q000502:physiology; D005323:Fetal Monitoring / Q000295:instrumentation / Q000379:methods*; D006321:Heart / Q000502:physiology; D006801:Humans; D009068:Movement; D012119:Respiration; D013909:Thorax / Q000196:embryology; D014465:Ultrasonics / Q000295:instrumentation; D014463:Ultrasonography