Columbia subject headings:
Harvard subject headings:
Comics (Graphic works)
Extraterrestrial beings--Comic books, strips, etc.
Graphic novels
Superhero comics
Superheroes--Comic books, strips, etc.
Superman (Fictitious character)--Comic books, strips, etc.
Princeton subject headings:
Comics (Graphic works)
Fiction.
Heroes--Comic books, strips, etc.
Superman (Fictitious character)--Comic books, strips, etc.