Deep Learning, Ian Goodfellow, Yoshua Bengio, and Aaron Courville, 2016 (MIT Press) - An authoritative textbook covering the bias-variance tradeoff, generalization, and regularization in deep neural networks.
CS229 Lecture Notes - Supervised Learning, Andrew Ng, 2018 - Lecture notes from a popular machine learning course, offering a clear explanation of the bias-variance tradeoff.