Liens

Abramowitz and Stegun: Handbook of Mathematical Functions
AMS books online
J. Derezinski: Bounded operators
J. Derezinski: Operators on L2(Rd)
J. Derezinski: Unbounded operators
Encyclopaedia of Mathematics
V. Jaksic: Topics in spectral theory
Maths biographies
Stanford encyclopedia of philosophy
Wolfram: Mathematical functions
Wolfram: Mathworld