BB, as far as I know the melody by Goguel is no longer used or at any rate was heavily modified by Hanns Eisler after the war, but Goguel's name has been kept out of respect. Langhoff and Esser are the 'official' authors but if you have a look at the extract from Langhoff's book cited above you'll realise that it isn't easy to determine 'real' authorship. I've wondered whether the man he 'commissioned' to write the first lyrics was, in fact, Esser, but I can't find out from the book. Maybe I missed something.