Hey Michael,
there is nothing (afaik) from our side, however there are many great online sources that explain the topic thoroughly.
As for us, we implemented it so that it is possible to use both Fresnel IOR maps as well as Specular maps. There is some internal formula that calculates Specular off of IOR and vice-versa (0.5 Specular == 1.5 IOR).
I hope this is enough (I am not a scholar on the subject),
Jan
Something like this may contain closer information:
https://www.programmersought.com/article/9101852439/ , if that's what you desire