Deep Learning, Ian Goodfellow, Yoshua Bengio, and Aaron Courville, 2016 (MIT Press) - This book is a standard reference for deep learning, with Chapter 10 providing a detailed explanation of recurrent neural networks, including the unrolling concept and Backpropagation Through Time (BPTT).
CS224N: Natural Language Processing with Deep Learning, Lecture Notes: Recurrent Neural Networks, Christopher Manning, 2023 (Stanford University) - These lecture notes from Stanford's highly-regarded CS224n course offer a clear and accessible explanation of recurrent neural networks, the concept of unrolling, and the Backpropagation Through Time (BPTT) algorithm, along with practical examples.