Introduction to Linear Algebra, Gilbert Strang, 2016 (Wellesley-Cambridge Press) - A fundamental textbook providing a rigorous and intuitive foundation in linear algebra, including a detailed treatment of matrix multiplication and its properties.
Mathematics for Machine Learning, Marc Peter Deisenroth, A. Aldo Faisal, and Cheng Soon Ong, 2020 (Cambridge University Press)DOI: 10.1017/9781108679904 - Specifically designed for machine learning practitioners, this book explains linear algebra concepts, such as matrix multiplication, in the context of their applications in ML.
numpy.matmul, NumPy Developers, 2023 - Official documentation for NumPy's matmul function and the @ operator, detailing their behavior for matrix multiplication with examples.
Linear Algebra (18.06SC), Gilbert Strang, 2011 (MIT OpenCourseWare) - A foundational MIT course offering comprehensive video lectures and materials on linear algebra, including in-depth discussions of matrix operations and their interpretations.