added one more link to readme about hopfield

README.md

@@ -125,6 +125,7 @@ They generate dummy data, where one can set different parameters.
     - [activation functions](https://towardsdatascience.com/creating-neural-networks-from-scratch-in-python-6f02b5dd911)
     - [hopfield layer](https://ml-jku.github.io/hopfield-layers/)
     - [more on hopfield](https://github.com/takyamamoto/Hopfield-Network/blob/master/network.py)
+    - [hopflied + mlp](https://link.springer.com/chapter/10.1007/3-540-44868-3_22)
     - [rnn - theory](https://www.freecodecamp.org/news/the-ultimate-guide-to-recurrent-neural-networks-in-python/)
     - [rnn - implementation](https://towardsdatascience.com/recurrent-neural-networks-rnns-3f06d7653a85)
     - [rnn - implementation](https://medium.com/@VersuS_/coding-a-recurrent-neural-network-rnn-from-scratch-using-pytorch-a6c9fc8ed4a7)