<Li> <P> Jasper Johns, Flag, 1954--55 (dated 1954) </P> </Li> <P> Jasper Johns, Flag, 1954--55 (dated 1954) </P> <Li> <P> Andy Warhol, Marilyn Diptych 1962 </P> </Li> <P> Andy Warhol, Marilyn Diptych 1962 </P>

Who is considered the founder of pop art