add citaion and original license

README.md

@@ -16,7 +16,22 @@ source_datasets:
 This dataset is derived from the [GermanQuAD](https://www.deepset.ai/germanquad) dataset.
 
 This dataset takes the testset and represents it as a corpus in the [BEIR](https://github.com/beir-cellar/beir) information retrieval benchmark format.
+Corpus and query ids have been added.
 The corresponding qrels can be found [here](hf.co/datasets/rasdani/germanquad-retrieval-qrels).
 
 
 Full credit for the original dataset goes to the [authors](https://arxiv.org/abs/2104.12741) of the GermanQuAD [dataset](https://huggingface.co/datasets/deepset/germandpr).
+
+The original dataset is licensed under [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/).
+
+Citation for the original dataset:
+```
+@misc{möller2021germanquad,
+      title={GermanQuAD and GermanDPR: Improving Non-English Question Answering and Passage Retrieval}, 
+      author={Timo Möller and Julian Risch and Malte Pietsch},
+      year={2021},
+      eprint={2104.12741},
+      archivePrefix={arXiv},
+      primaryClass={cs.CL}
+}
+```