Update 'README.md'

README.md

@@ -52,6 +52,7 @@ ___
 - [Metric Prefixes](https://en.wikipedia.org/wiki/Metric_prefix)
 - [Offa's Dyke](https://en.wikipedia.org/wiki/Offa%27s_Dyke)
 - [Brassica Oleracea is cabbage, brussel sprouts, broccoli, cauliflower, kale](https://en.wikipedia.org/wiki/Brassica_oleracea)
+- [Wagner Group](https://en.wikipedia.org/wiki/Wagner_Group)
  
 ## [Mathematics and Theoretical Computer Science](mathematics.md)
 - [OEIS: The Online Encyclopedia of Integer Sequences](https://oeis.org/)