@article{JMLR:v18:16-603,
  author  = {Thang D. Bui and Josiah Yan and Richard E. Turner},
  title   = {A Unifying Framework for Gaussian Process Pseudo-Point Approximations using Power Expectation Propagation},
  journal = {Journal of Machine Learning Research},
  year    = {2017},
  volume  = {18},
  number  = {104},
  pages   = {1--72},
  url     = {http://jmlr.org/papers/v18/16-603.html}
}