Weitzmann.—History of Pianoforte Playing.
Parry.—Evolution of the Art of Music, Chapter XII.
Shedlock.—The Pianoforte Sonata, Chapter VII.
Naumann.—History of Music, Vol. II, Chapter XXXII.
Schindler.—Life of Beethoven.
Other lives of Beethoven, especially that in Grove’s Dictionary.
For musical illustrations, consult the works of Beethoven, especially
the Pianoforte sonatas, published complete in all the cheap editions.