According to papers:
- Neural Machine Translation and Sequence-to-sequence Models: A Tutorial (Neubig et al.) (https://arxiv.org/abs/1703.01619)
- Neural Machine Translation by Jointly Learning to Align and Translate (Bahdanau et al.) (https://arxiv.org/abs/1409.0473)
- Tensorflow Sequence-To-Sequence Tutorial (https://www.tensorflow.org/tutorials/seq2seq)