@article{JMLR:v13:martinez12a,
  author  = {Aleix Martinez and Shichuan Du},
  title   = {A Model of the Perception of Facial Expressions of Emotion by Humans: Research Overview and Perspectives},
  journal = {Journal of Machine Learning Research},
  year    = {2012},
  volume  = {13},
  number  = {50},
  pages   = {1589--1608},
  url     = {http://jmlr.org/papers/v13/martinez12a.html}
}