"Soap bubbles" and "gauze thread" drain tube tests.

@article{OConnor2001SoapBA,
  title={"Soap bubbles" and "gauze thread" drain tube tests.},
  author={C. J. O'Connor and Sara R Davies and Michael S Stix},
  journal={Anesthesia and analgesia},
  year={2001},
  volume={93 4},
  pages={1082}
}