@article{Weber91Degree,
  author = {Andreas Weber and Helmut Seidl},
  title = {On the {D}egree of {A}mbiguity of {F}inite {A}utomata},
  journal = {Theor. Comput. Sci.},
  year = 1991,
  pages = {325-349},
  volume = {88},
  number = {2},
}