Hello, I was searching for some books/resources to help me understand Game Engines development better to give me some boost to fix more bugs and continue documenting the Animation API, I went through 2 good books and I would like to share them (Maybe they can help with the undocumented parts):
Game Engine Architecture By Jason Gregory, this book specifically has perfect explanation for the Animation Blending, how animation clips and procedural animation work.
also there is russians and persian repos, which contain most new papers, but so restricted to the people out of countries.
there is a book off topic to game engine but on computer graphic with java and opengl, used in universities which can be supplementary:
[Scott Gordon](zlibrary-asia.se. Scott Gordon)