Unstable asthma and theophylline.

@article{Stern1991UnstableAA,
  title={Unstable asthma and theophylline.},
  author={Myra Stern and Duncan M. Geddes and John H. Lienhard V Collins and Timothy L. Evans},
  journal={BMJ},
  year={1991},
  volume={303 6813},
  pages={1317-9}
}