I'm not familiar with old stuff either. To me I could describe these as a bit of @Aaron Blaise kind of cartoony shape language with a more tight rendering like those hero comics do (quite nicely rendered flesh and other forms). I've seen Boban Savić GETO's work, this particular person's style do align more with the reference you give there. It's /geto on artstation (I could not post link or it might get blocked) and /boban-savic-geto on deviant art, although their shape isn't as "stylized" as what you linked. I think nowadays you could look up some coloured pencil drawings, they got the similar texture, it's just matter of finding the shape you like.