| APA | Smart Define. (1970). ultrasound examination in obstetrics thesaurus. Retrieved October 1, 2026, from https://smartdefine.org/ultrasound_examination_in_obstetrics/thesaurus/broader |
| Chicago | Smart Define. 1970. "ultrasound examination in obstetrics thesaurus" https://smartdefine.org/ultrasound_examination_in_obstetrics/thesaurus/broader (accessed October 1, 2026). |
| Harvard | Smart Define 1970, ultrasound examination in obstetrics thesaurus, Smart Define, viewed 1 October, 2026, <https://smartdefine.org/ultrasound_examination_in_obstetrics/thesaurus/broader>. |
| MLA | Smart Define. "ultrasound examination in obstetrics thesaurus" 1 January 1970. Web. 1 October 2026. <https://smartdefine.org/ultrasound_examination_in_obstetrics/thesaurus/broader> |