@article{Str:92a,
  author = {T. Streicher},
  volume = {2},
  year = {1992},
  number = {1},
  journal = {Math.~Struct.~Comput.~Sc.},
  title = {Dependence and independence results for (impredicative) calculi of
           dependent types.},
  pages = {29-54},
}