Merge pull request #2 from Azzaare/addcit

Added citation graphs (arxiv/US patent) from SNAP

Author: sbromberger

data/README.md

@@ -1,9 +1,14 @@
 The following graphs have been adapted:
 
+- [arxiv-cit-hep-ph](https://snap.stanford.edu/data/cit-HepPh.html)*
+- [arxiv-cit-hep-th](https://snap.stanford.edu/data/cit-HepTh.html)*
 - [as-caida](https://snap.stanford.edu/data/as-caida.html)
 - [ca-astroph](https://snap.stanford.edu/data/ca-AstroPh.html)
 - [ca-condmat](https://snap.stanford.edu/data/ca-CondMat.html)
 - [ego-twitter](https://snap.stanford.edu/data/egonets-Twitter.html)
 - [email-enron](https://snap.stanford.edu/data/email-Enron.html)
 - [facebook-combined](https://snap.stanford.edu/data/egonets-Facebook.html)
+- [patent-cit-us](https://snap.stanford.edu/data/cit-Patents.html)*
 - [soc-slashdot0902](https://snap.stanford.edu/data/soc-Slashdot0902.html)
+
+*Note that the three citation graphs have a `csv` file matching the nodes ids with the articles/patents ids. Hence users can match the node ids with available meta-data on SNAP.