I don't follow you. I already laid it out -
Benton v Maryland, 13'th footnote. Justice Marshall writing for the Court, cites Black's dissent in
Bartkus - since Marshall looks to it to support his view of the incorporation of the Fifth amendment, we may logically infer that he shares Black's reasoning, at least to some extent. And it is cited within the
Benton decision itself. Therefore, Black's reasoning is shared by at least one other Justice, and by at least one subsequent decision of the Court.
Was there something else you were looking for as proof?