@incollection{HoSt:98,
  publisher = {Oxford University Press},
  author = {M. Hofmann and T. Streicher},
  pages = {83-111},
  title = {The groupoid interpretation of type theory},
  series = {Oxford Logic Guides},
  booktitle = {Twenty-five years of constructive type theory},
  year = 1998,
  volume = 36,
}