@Article{alti:qarrows,
  author = 	 {Juliana K. Vizzotto and Thorsten Altenkirch and Amr Sabry},
  title = 	 {Structuring Quantum Effects: Superoperators as Arrows},
  journal={Mathematical Structures in Computer Science},
  volume={16},
  number={03},
  pages={453--468},
  year={2006},
  publisher={Cambridge University Press}
}