Looking for a certain skill books

[The Fierce Deity]

While I don't need them for the skill levels, I pretty much have done everything I wanted to, but I am missing 4 skill books from having the complete set.

Still need speech, drinking, and unarmed 4, as well as agility 3.

I heard occasionally traders you run across in fast travel will have a skill book but I have not encountered that yet.

Some of the skill #4 books I found were in clever hidden spots like spear and survival 4, so I am wondering if its the same for the four I dont have yet.

If anyone has found them I would appreciate if you could tell me where you found it. I did a basic web search for them but no dice.

Of course I could console them in, but that spoils the fun.