Finding an article about modelling with 2 intercepts


I read an article that discussed modelling with 2 intercepts in stan, but I forgot where I found this article. Now I am building models with 2 intercepts, which turns out to be bad, so I want to find out this article and read it again.

Does somebody know this article? Please let me know if you can find it, or you would like to provide some ideas about modelling with 2 intercepts. Much appreciated!

Does this help? If not, do you remember the intended use (or scientific field of the authors) of the two intercept model?

Thanks! I guess this article was the one that I read, and it now helps as well. I also find another article about model non-identifiability.