All things spectral filtering :)
[x] "Learning Linear Dynamical Systems via Spectral Filtering" - Hazan, Cyril, Karan
[x] Hankel Operators and Applications (Lecture Notes) — Aleksey Kostenko
tables of stuff and other resources
orthogonal polynomials and hypergeometrics
the Hilbert matrix, explicit diagonalizations, and generalizations
General Hankel matrices
Sturm-Liouville