E-Books. They're like traditional, physical books, but electronic.

• Project Gutenberg
• University of Michigan Historical Mathematics Collections
• Cornell Historical Math Monographs

• The Concise Oxford Dictionary of Mathematics by Christopher Clapham; James Nicholson
• Dictionary of Algebra, Arithmetic and Trigonometry by Steven G. Krantz
• Dictionary of Algebra, Arithmetic and Trigonometry by Steven G. Krantz
• Dictionary of Analysis Calculus and Differential Equations by Stan Gibilisco; Douglas N. Clark (Editor)
• Dictionary of Applied Math for Engineers and Scientists by Emma Previato
• Dictionary of Classical and Theoretical Mathematics by Catherine Cavagnaro; William T. Haight
• The Cambridge Dictionary of Statistics by B. S. Everitt; Anders Skrondal
• The Penguin Dictionary of Mathematics by David Nelson (Editor)

• Fundamentals of Mathematics by H. Behnke (Editor); F. Bachmann (Editor); K. Fladt (Editor); S. H. Gould (Translator); W. Süss (Editor)
• Fundamentals of Mathematics : an introduction to proofs, logic, sets, and numbers by Bernd S. W. Schröder
• Encyclopaedia of Mathematics by Michiel Hazewinkel (Editor)
• Encyclopedic Dictionary of Mathematics by Mathematical Society of Japan Staff (Editor); Kiyosi Ito (Editor)
• Van Nostrand Reinhold Concise Encyclopedia of Mathematics by Walter Gellert
• The CRC Encyclopedia of Mathematics, Third Edition - 3 Volume Set by Eric W. Weisstein
• Wolfram Mathworld

• MathNewBase: database of math handbooks
• Concise Handbook of Mathematics Physics and Engineering Sciences by Andrei D. Polyanin; Alexei I. Chernoutsan
• Algorithms and Theory of Computation by Marina Blanton
• Handbook of Mathematical Sciences by William H. Beyer (Editor)
• Handbook of Applicable Mathematics by Walter Ledermann; R. F. Churchhouse; S. Vajda; E Lloyd
• Handbook of Discrete and Combinatorial Mathematics by Kenneth H. Rosen (Editor)
• Handbook of Linear Algebra by Leslie Hogben (Editor); Richard Brualdi (Editor); Anne Greenbaum (Editor); Roy Mathias (Editor)
• REA's Handbook of Mathematical Formulas, Tables and Transforms by M. Fogiel
• Handbook of Mathematical Functions by Milton Abramowitz (Editor); Irene A. Stegun (Editor)
• The Handbook of Mathematics and Computational Science by Horst Stöcker; John W. Harris
• Handbook of Mathematical Formulas and Integrals by Alan Jeffrey; Hui Hui Dai
• Handbook of Applied Mathematics for Engineers and Scientists by Max Kurtz
• Beta Mathematics Handbook by Lennart Rade; Bertil Westergren
• Technology Mathematics Handbook by Jan J. Tuma

Most recent edition listed. To see all editions held by the Libraries, click on "See all versions" in the Library Search record.

• Physics (Cutnell & Johnson): 9th ed. (2012).
• Fundamentals of Physics (Walker, Halliday, & Resnick): 10th ed. (2014).
• Introduction to Optics (Pedrotti): 3rd ed. (2007).
• Mathematical Methods in the Physical Sciences (Boas): 3rd ed. (2006).
• Data Reduction and Error Analysis for the Physical Sciences (Bevington): 3rd ed. (2003).
• Introduction to Electrodynamics (Griffiths): 4th ed. (2017).
• Classical Mechanics (Taylor): 2005.
• Thermal Physics (Finn): 2nd ed. (1993).
• Principles of Quantum Mechanics (Shankar): 2nd ed. (1994).
• Introduction to Solid State Physics (Kittel): 8th ed. (2005).
• Classical Electrodynamics (Jackson): 3rd ed. (1999).
• Modern Quantum Mechanics (Sakurai): 2nd ed. (2011).