Digital Library of Mathematical Functions
- http://dlmf.nist.gov/
- This mockup gives an idea of the current ideas about the design and organization of the new Digital Library; these ideas are, of course, subject to change. Content only is only available in a few places.
EquationSheet.com
- http://www.equationsheet.com/
- Searchable directory, arranged by field, of equations, constants, symbols and SI units. Also features LaTEX utilities, software links.
Math Assistance
- http://www.ercangurvit.com/
- Lists rules and formulas for a number of mathematical subjects, such as plotting graphics, functions, factoring, derivatives, integrals, matrices, vectors, and numerical analysis. In English, French and Turkish languages.