@inproceedings{MnihHinton2005,
  title={Learning Nonlinear Constraints with Contrastive Backpropagation},
  author={Mnih, Andriy and Hinton, Geoffrey},
  booktitle={Proceedings of International Joint Conference on Neural Networks (IJCNN)},
  volume={2},
  pages={1302--1307},
  year={2005},
}