@article{Epstein2010,
  author    = {Paul Epstein},
  title     = {{\"U}ber Elementarkettenbr{\"u}che, lineare Substitutionen und indefinite bin{\"a}re quadratische Formen : I.},
  journal   = {Journal f{\"u}r die reine und angewandte Mathematik},
  volume    = {149},
  number    = {1-2},
  pages     = {57 -- 88},
  year      = {2010},
}