Citation extraction as csv not a doi

[haniehsaeedi]

As we have discussed before, I think we should provide a doi per each data extraction from OBIS. At the moment we only provide the CSV citations including a long list of citations. When someone is working on big data with multiple dataset citations, this could be problematic to include all the citations in the main text, and they should go usually to the supplementary file, which might affect the visibility of the citations. It will be nice if we could provide dois per each date extraction.