Most of the source is myself really(being mixed Han Chinese), mostly going off on memory of reading and researching into Chinese fictional media, aka. lots of novels, chinese comics, TV, movies etc.
Can't also exactly link all the worst offending stuff either, cause they're on pirated sites or behind paywall(or just being really old and hard to find), also I'll admit I haven't bother looking into this sort of stuff in about 10 months now. But if you've been keeping up with the recent past few years of political climate regarding China, then no doubt the recent propagandas will fuel the next "season"(eg. 2021-23) of fictional writing.
This is just one of those weird stuff that's some-what commonly known, can be hard to find despite being also somewhat commonly around, it's like a hidden rule to not really speak about it on ALL sides of the Asia isles, and just let it happen lol.
PS. Gonna leave this short, don't wanna turn this into a essay...if you or anyone else want more info and such, PM me.