Any good resources for trying to build a counter-propagation model?

I understand that it is basically input layer->SOM->Grossberg/outstar layer

The part giving me trouble is the Grossberg/outstar layer. It feels like I can find next to no information about it (and counter-propagation in general) searching online. For now, I have a dense layer where the outstar layer would go, and I'm getting roughly the same results as the NN made of 7 dense layers I'm comparing my model against. That certainly doesn't feel right, and I'm pretty desperate for some clarification on the subject lol

Additionally, is there a reason why there's no discourse on counter-propagation models? Multiple variations of the phrase got zero results on this subreddit. I understand it was pretty popular before the use of multiple hidden layers, any reason why it seems to be unnoticed in modern times?