[morelisp]

You can't open the conversation offering "the entire history of math since ancient times" and then demand thoroughly modern things like "an actual published result that was cited by other results" as counter-evidence.

Nonetheless many of the examples in the above links still fit your criteria.

[_xnmw]

A published result that cites another result is not "a thoroughly modern thing". Mathematicians have been citing each other since Pythagoras and Avicenna.