Maple has a large number of initially defined functions, as well as distributed knowledge about these functions. For example LambertW, `evalf/LambertW`, and `int/LambertW` all exist in the Maple system.

The major reference for functions in Maple is Abramowitz and Stegun.

Abramowitz, M., and Stegun, I. Handbook of Mathematical Functions. New York: Dover Publications Inc., 1965. 1046 pp.

Spanier, J., and Oldham, K. An Atlas of Functions. Washington D.C.: Hemisphere Publishing Corp., 1987. 700 pp.

Other References include the following:

Gradshteyn, I.S., and Ryzhik, I.M. Table of Integrals, Series and Products. 5th ed. Edited by Alan Jeffrey. London: Academic Press, 1994.

Prudnikov, A.P.; Brychkov, Yu.A.; and Marichev, O.I. Integrals and Series. 6 vols. Edited by N.M. Queen. New York: Gordon and Breach Science Publishers, 1986.

Zwillinger, Daniel, ed. Standard Mathematical Tables and Formulae. 30th ed. Boca Raton, USA: CRC Press, 1996.