@misc{indiciaea9c9fbd9e9da,
  title = {[Difficulty in determining ultrasonic attenuation values from selective echograms].},
  author = {M Petzold and K Gräfenstein and K V Jenderka and K P Richter},
  year = {1990},
  url = {https://pubmed.ncbi.nlm.nih.gov/2236549/},
  note = {Source identifier: 2236549}
}