Random error with the FEV1 = case for absolute values.

@article{Vale1981RandomEW,
  title={Random error with the FEV1 = case for absolute values.},
  author={J. R. Vale and Amund Gulsvik and Johny Steinar Kongerud},
  journal={Lancet},
  year={1981},
  volume={2 8241},
  pages={313}
}