Introduction to Linear Algebra, Gilbert Strang, 2016 (Wellesley-Cambridge Press) - An essential textbook offering a clear introduction to linear algebra concepts, including the definition and role of scalars. (5th edition)
Deep Learning, Ian Goodfellow, Yoshua Bengio, and Aaron Courville, 2016 (MIT Press) - Covers mathematical foundations for deep learning, introducing scalars as fundamental numerical elements in data and model representation.