@misc{indiciae88964e52bdc1,
  title = {Echocardiographic contrast studies: initial experience.},
  author = {J B Seward and A J Tajik and J G Spangler and D G Ritter},
  year = {1975},
  url = {https://pubmed.ncbi.nlm.nih.gov/1123933/},
  note = {Source identifier: 1123933}
}