@article{simao2009transformational,
  author={Sim{\~a}o, A. and Maldonado, J.C. and da Silva Bigonha, R.},
  title={A transformational language for mutant description},
  journal={Computer Languages, Systems \& Structures},
  year={2009},
  volume={35},
  number={3},
  pages={322--339}
}