Interesting and very nice made cassette players fan pages
http://walkman-archive.com/gadgets/index.html
https://www.petervis.com/walkmans/Vintage%20Walkmans.html
Online forums with tons of useful information, where you can ask questions
http://tapeheads.net
http://www.stereo2go.com
Free Service manuals
elektrotanya.com
hifiengine.com
List of cassette players
https://www.vintagecassette.com/
http://vintagecassettes.com/
http://www.sonyvintage.com/
http://www.analogaudio.narod.ru/handbook/
http://wikiboombox.com/tiki-index.php?page=Manufacturers
