Best I could find is a shady Wikipedia article referencing a controversial study, not exactly compelling evidence... Nevermind that scientists cannot even agree on a standard valid unit of measurement for "intelligence".
edit: Just google "white men can't jump", i think it's pretty obvious
Well I mean, the evidence is pretty strong. Several IQ studies, vastly overrepresented among Nobel Prize winners, Fields Medal winners, ACM Turing Award winners, 6 out of 19 chess champions, etc. I think the disproportionate influence theory is an extremely unlikely explanation (6 out of 19 chess champions? no, that's not because of disproportionate influence).
edit: Just google "white men can't jump", i think it's pretty obvious