The Maylath/Hackh Grand Conservatory Method for Piano is currently under an editor's name, Eberhard. While Maylath and Hackh took works by other composer, theirs is at least the original compilation -- the choice of works were theirs, not Eberhard's. Eberhard did an edition, and may have done a translation from German as well, but the "composer" needs to be Maylath and Hackh.
I can change this, but I'm not sure how to do two authors. The same will apply, if anyone ever uploads it, to the original Taffanel/Gaubert Methode for flute.