diff -r e68f0ef37e77 -r 73e29215aaa4 doc/references.bib
--- a/doc/references.bib	Sat Oct 07 17:03:30 2017 +0200
+++ b/doc/references.bib	Wed Oct 17 22:55:02 2018 +0200
@@ -43,6 +43,17 @@
   pages =        {67--118}
 }
 
+@article{VF2PP,
+  author =       {Alp\'ar J\"uttner and  P\'eter Madarasi},
+  title =        {{VF2++} — An improved subgraph isomorphism algorithm},
+  journal =      {Discrete Applied Mathematics},
+  year =         {2018},
+  volume =       {242},
+  pages =        {69--81},
+  url =          {https://doi.org/10.1016/j.dam.2018.02.018}
+}
+
+
 
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