Question: Both George Brütsin IV and Gustav Mahler are considered what?
Sentence (from "Erwin Ratz"): He is best known for his work "Einführung in die musikalische Formenlehre" ("Introduction to Musical Form"), which is devoted primarily to the work of Bach and Beethoven, and for his role in editing Mahler's works as President of the 'International Gustav Mahler Gesellschaft' in Vienna.
Relevant evidence: No