@article{LocalSymmetry,
  title = "Local symmetry and triangle laws are sufficient for metrisability",
  author = "A. W. Roscoe and P.J. Collins",
  year = "1985",
  journal = "{Colloquia Mathematica Societatis Janos Bolyai 41}",
  pages = "177--181",
  url = "http://ww.cs.ox.ac.uk/people/bill.roscoe/publications/16.pdf",
}