This revised edition was prepared with reference to all manuscript sources that could be found: the sketch, final (engraving) copy, a corrected proof of the first printed edition and some communications between the composer and his publisher. Since there were several editions already in the composer´s lifetime, which provided opportunities for changes and corrections, the present revised edition differs from the preceding one in only a few respects. The changes include dynamics and accents; precise endings of crescendos have been adjusted. Not a single wrong note could be found. (Peter Bartók, taken from the preface)