I would have thought that those of you who post here would know this, but - A.P. Carter copyrighted a great number of songs, perhaps most of those attributed to him, that, in some version, were public domain at the time. This was, and is, not uncommon, but he was known for doing this. In most cases, he "refined" them to suit his own sensibilities, and that is probably a good thing, as he had a marvelous sense of their musicality. Many Carter Family songs probably would not have become as popular as they have did and have remained if A.P. had not tailored them to suit (no pun intended) the musical tastes of his time and since.