Relative completeness with respect to two unary functions

@article{Pantovic2001RelativeCW,
  title={Relative completeness with respect to two unary functions},
  author={Jovanka Pantovic and Ratko Tosic and Gradimir Vojvodic},
  journal={Discrete Applied Mathematics},
  year={2001},
  volume={113},
  pages={337-342}
}