https://armchairarcade.com/perspectives/2018/03/12/pay-what-you-want-for-unreal-engine-4-ai-programming-essentials-machine-learning-with-r-and-more-in-the-humble-book-bundle-a-i-by-packt/
Pay what you want for Unreal Engine 4 AI Programming Essentials, Machine Learning with R, and more in The Humble Book Bundle: A.I. by Packt