The data sources used in the documentation no longer exist

[choooze]

Hello guys.

I found that there is no more data sources that you used in documentation, like:
https://github.com/pybel/pybel-notebooks/blob/master/summary/Citation%20Analysis.ipynb

No more BEL models in repo: https://tor-2.scai.fraunhofer.de/gf/project/bms/

Could you please update documentation regarding to the new data sources?