https://en.wikipedia.org/wiki/Chollima_Movement
Citation #2 points to a book that collates many sources. Here’s what it has to say:
Wikipedia is just a collection of opinions laundered by loosely-relevant citations appearing next to them (or in this case, completely irrelevant ones).
It pretty much always comes down to this, and because of the century of red scare that preceded us we are always on the disadvantaged side regarding the amount of good truthful sources that are in a language you can understand.
They can always pull the “goverment lies” card but when we do they scuff at us because we’re apparently mindwashed by the USSR or some local communist org