Variance and Reliability in estimates of OC use.

@article{Hendershot1981VarianceAR,
  title={Variance and Reliability in estimates of OC use.},
  author={Gerry E. Hendershot and William D. Mosher},
  journal={American journal of public health},
  year={1981},
  volume={71 3},
  pages={316-7}
}