@article{JMLR:v13:hyttinen12a,
  author  = {Antti Hyttinen and Frederick Eberhardt and Patrik O. Hoyer},
  title   = {Learning Linear Cyclic Causal Models with Latent Variables},
  journal = {Journal of Machine Learning Research},
  year    = {2012},
  volume  = {13},
  number  = {109},
  pages   = {3387--3439},
  url     = {http://jmlr.org/papers/v13/hyttinen12a.html}
}