That first link (https://www.win.tue.nl/~aeb/linux/hh/tempest.pdf) is absolutely fascinating.

Also I think this paper is amazing - http://s3.eurecom.fr/docs/ccs18_camurati_preprint.pdf

"The well-known electromagnetic (EM) leakage from digital logic is inadvertently mixed with the radio carrier, which is amplified and then transmitted by the antenna. We call the resulting leak “screaming channels”"

You might find this interesting too, leaking AM emissions from a computer by twiddling the memory bus - https://github.com/fulldecent/system-bus-radio

I made a silly program to play .wav files based on that.