Original sentence: During his retirement Graf served as a volunteer for a businessman's association, the Niederosterreichische Gewerb-Verein, which he had helped to found in 1839
Edited sentence: 19th-Century Music 7:251-265.During his retirement Graf served as a volunteer for a businessman's association, the Niederosterreichische Gewerb-Verein ("Lower Austrian Industrial Association"), which he had helped to found in 1839.However, a number of modern builders have created new copies of Graf pianos, and these non-dilapidated instruments have been adopted by a variety of modern performers for both concerts and recordings; see External links below.The surviving Graf instruments are about two centuries old; the musicologist Robert Winter has voiced strong criticism of performers who choose to use historical instruments, including Graf pianos, that may sound very poorly such a great passage of time.Winter, Robert (1987) The emperor's new clothes: Nineteenth-century instruments revisited