Meta-datasets (GLUE/XTREME/...) – Special care to attributions and citations
As @yoavgo suggested, there should be the possibility to call a function like  nlp.bib that outputs all bibtex ref from the datasets and models actually used and eventually nlp.bib.forreadme that would output the same info + versions numbers so they can be included in a readme.md file. Actually, double checking with @mariamabarham, we already have this feature I think.

It's like this currently:
```python
>>> from nlp import load_dataset
>>> 
>>> dataset = load_dataset('glue', 'cola', split='train')
>>> print(dataset.info.citation)
@article{warstadt2018neural,
  title={Neural Network Acceptability Judgments},
  author={Warstadt, Alex and Singh, Amanpreet and Bowman, Samuel R},
  journal={arXiv preprint arXiv:1805.12471},
  year={2018}
}
@inproceedings{wang2019glue,
  title={{GLUE}: A Multi-Task Benchmark and Analysis Platform for Natural Language Understanding},
  author={Wang, Alex and Singh, Amanpreet and Michael, Julian and Hill, Felix and Levy, Omer and Bowman, Samuel R.},
  note={In the Proceedings of ICLR.},
  year={2019}
}

Note that each GLUE dataset has its own citation. Please see the source to see
the correct citation for each contained dataset.
```

What do you think @dseddah? Looks good but why would there be a difference between the ref in the source and the one to be printed?  Yes, I think we should remove this warning @mariamabarham.

It's probably a relic of tfds which didn't have the same way to access citations. 
Meta-datasets are interesting in terms of standardized benchmarks but they also have specific behaviors, in particular in terms of attribution and authorship. It's very important that each specific dataset inside a meta dataset is properly referenced and the citation/specific homepage/etc are very visible and accessible and not only the generic citation of the meta-dataset itself.

Let's take GLUE as an example:

The configuration has the citation for each dataset included (e.g. [here](https://github.com/huggingface/nlp/blob/master/datasets/glue/glue.py#L154-L161)) but it should be copied inside the dataset info so that, when people access `dataset.info.citation` they get both the citation for GLUE and the citation for the specific datasets inside GLUE that they have loaded.