Long Short-Term Memory, Sepp Hochreiter, Jürgen Schmidhuber, 1997Neural Computation, Vol. 9 (MIT Press)DOI: 10.1162/neco.1997.9.8.1735 - The original academic paper introducing the Long Short-Term Memory (LSTM) network.
Deep Learning, Ian Goodfellow, Yoshua Bengio, Aaron Courville, 2016 (MIT Press) - A comprehensive textbook providing a detailed theoretical explanation of LSTMs within the context of recurrent neural networks.