<https://pubs.asahq.org/anesthesiology/article/129/5/1025/19969/Images-in-Anesthesiology-Early-Identification-of>
<http://schema.org/about>
"echocardiography"
<https://asa2.silverchair.com/anesthesiology/article/129/5/1025/19969/Images-in-Anesthesiology-Early-Identification-of>