@INPROCEEDINGS {28155,
author={A. Martins and R.  Astudillo},
doi={},
booktitle={International Conf. on Machine Learning - ICML},
title={From Softmax to Sparsemax: A Sparse Model of Attention and Multi-Label Classification},
year={2016},
month={June},
volume={48},
pages={1614-1623} 
}