@misc{indiciae1df910016edd,
  title = {Which heart valve?},
  author = {S A Nashef},
  year = {1990},
  doi = {10.1016/0140-6736(90)93159-m},
  url = {https://pubmed.ncbi.nlm.nih.gov/1978911/},
  note = {Source identifier: 1978911}
}