D. Lee, and H. Seung. Advances in Neural Information Processing Systems 13, Papers from
Neural Information Processing Systems (NIPS) 2000, Denver, CO, USA, page 556--562. MIT Press, (2000)
J. Devlin, M. Chang, K. Lee, and K. Toutanova. Proceedings of the 2019 Conference of the North American Chapter of
the Association for Computational Linguistics: Human Language Technologies,
NAACL-HLT 2019, Minneapolis, MN, USA, June 2-7, 2019, Volume 1 (Long
and Short Papers), page 4171--4186. Association for Computational Linguistics, (2019)