[j-pb]

Even if we ignore reprints, editorial series that rearrange papers (and make a paper citable more than one way), and proceedings (which often don't properly distinguish between papers, but use author + proceeding).

Science simply doesn't operate on journal published papers most of the time. The paper mills run so hot that you regularly cite preprints, that get exchanged between authors directly. It happens regularly that the proof is supposedly in the "full paper" only that the "full paper" was never published.