*-μ-semirings and *-λ-semirings

@article{Feng2005semiringsA,
  title={*-μ-semirings and *-λ-semirings},
  author={Feng Feng and Xianzhong Zhao and Young Bae Jun},
  journal={Theor. Comput. Sci.},
  year={2005},
  volume={347},
  pages={423-431}
}