https://paul.me.vt.edu/news/duggleby-karhunen-Loeve-cf.html
Computing the Karhunen-Loeve dimension of an Extensively Chaotic Flow Field Given a Finite Amount...
Computers and Fluids
https://researchportalplus.anu.edu.au/en/publications/a-karhunen-loeve-expansion-for-one-mode-open-quantum-harmonic-osc-2/
A karhunen-loeve expansion for one-mode open quantum harmonic oscillators using the eigenbasis of...
https://loeve-loeve.blogspot.com/
Loeve