That's definitely one of the papers that was referenced when writing the
algorithm. The module within NetworkX lists:
References
----------
[1] Luigi P. Cordella, Pasquale Foggia, Carlo Sansone, Mario Vento,
"A (Sub)Graph Isomorphism Algorithm for Matching Large Graphs",
IEEE Transactions on Pattern Analysis and Machine Intelligence,
vol. 26, no. 10, pp. 1367-1372, Oct., 2004.
http://ieeexplore.ieee.org/iel5/34/29305/01323804.pdf
[2] L. P. Cordella, P. Foggia, C. Sansone, M. Vento, "An Improved
Algorithm for Matching Large Graphs", 3rd IAPR-TC15 Workshop
on Graph-based Representations in Pattern Recognition, Cuen,
pp. 149-159, 2001.
http://amalfi.dis.unina.it/graph/db/papers/vf-algorithm.pdf
Chris