The Design of Approximation Algorithms
David P. Williamson & David B. Shmoys
Introduction to Linear Algebra 5th Edition
Gilbert Strang
Matrix Calculus (for Machine Learning and Beyond)
Alan Edelman, Steven G. Johnson
Proof and the Art of Mathematics: Examples and Extensions
Joel David Hamkins
Computers and Intractability: A Guide to the Theory of NP-completeness
Michael R. Garey & David S. Johnson