@misc{indiciae7a9e42440461,
  title = {Echocardiography (1).},
  author = {R L Popp},
  year = {1990},
  doi = {10.1056/nejm199007123230206},
  url = {https://pubmed.ncbi.nlm.nih.gov/2193226/},
  note = {Source identifier: 2193226}
}