View this amazing collection of rare, composer-edited sheet music from the Julliard School here: The Juilliard Manuscript Collection Website.
“In 2006 Juilliard received a trove of precious music manuscripts from the billionaire collector and financier Bruce Kovner. The collection includes autograph scores, sketches, composer-emended proofs and first editions of major works by Mozart, Bach, Beethoven, Brahms, Schumann, Chopin, Schubert, Liszt, Ravel, Stravinsky, Copland and other masters of the classical music canon. Many of the manuscripts had been unavailable for generations. Among the items are the printer’s manuscript of Beethoven’s Ninth Symphony, complete with Beethoven’s hand-written amendments, that was used for the first performance in Vienna in 1824; Mozart’s autograph of the wind parts of the final scene of The Marriage of Figaro; Beethoven’s arrangement of his monumental Große Fuge for piano four hands; Schumann’s working draft of his Symphony No. 2; and manuscripts of Brahms’s Symphony No. 2 and Piano Concerto No. 2. The entire collection has since been digitized and can be viewed online.” Source: http://en.wikipedia.org/wiki/Juilliard_School