@article{offutt1996experimental,
  author={Offutt, A.J. and Lee, A. and Rothermel, G. and Untch, R.H. and Zapf, C.},
  title={An experimental determination of sufficient mutant operators},
  journal={ACM Transactions on Software Engineering and Methodology (TOSEM)},
  year={1996},
  volume={5},
  number={2},
  pages={99--118}
}