[docs] include proper citations (#74)

README.md

@@ -42,3 +42,15 @@ See the [CONTRIBUTING](CONTRIBUTING.md) file for how to help out.
 ## License
 
 fairscale is licensed under the [BSD-3-Clause License](LICENSE).
+
+fairscale.nn.pipe is forked from [torchgpipe](https://github.com/kakaobrain/torchgpipe), Copyright 2019, Kakao Brain, licensed under [Apache License](http://www.apache.org/licenses/LICENSE-2.0).
+
+fairscale.nn.model_parallel is forked from [Megatron-LM](https://github.com/NVIDIA/Megatron-LM), Copyright 2020, NVIDIA CORPORATION, licensed under [Apache License](http://www.apache.org/licenses/LICENSE-2.0).
+
+## References
+
+Here is a list of all authors on relevant research papers this work is based on:
+
+* torchgpipe: Chiheon Kim, Heungsub Lee, Myungryong Jeong, Woonhyuk Baek, Boogeon Yoon, Ildoo Kim, Sungbin Lim, Sungwoong Kim. [[Paper](https://arxiv.org/pdf/2004.09910.pdf)] [[Code](https://github.com/kakaobrain/torchgpipe)]
+* ZeRO: Samyam Rajbhandari, Jeff Rasley, Olatunji Ruwase, Yuxiong He. [[Paper](https://arxiv.org/pdf/1910.02054.pdf)] [[Code](https://github.com/microsoft/DeepSpeed)]
+* Megatron-LM: Mohammad Shoeybi, Mostofa Patwary, Raul Puri, Patrick LeGresley, Jared Casper, Bryan Catanzaro. [[Paper](https://arxiv.org/pdf/1909.08053.pdf)][[Code](https://github.com/NVIDIA/Megatron-LM)]