@article{Friese11Minimization,
  author = {Sylvia Friese and Helmut Seidl and Sebastian Maneth},
  title = {Earliest {N}ormal {F}orm and {M}inimization for {B}ottom-{U}p {T}ree {T}ransducers},
  journal = {International Journal of Foundations of Computer Science},
  year = 2011,
  pages = {1607-1623},
  volume = {22},
  number = {7},
}