@inproceedings{MuBird2000:OnBuilding,
  author = "Shin-Cheng Mu and Richard Bird",
  booktitle = "First Asian Workshop on Programming Languages and Systems",
  title = "On Building Trees with Minimum Height, Relationally",
  url = "http://www.comlab.ox.ac.uk/people/richard.bird/online/MuBird2000OnBuilding.pdf",
  year = "2000",
}