Willibald Nagel.—Beethoven und seine Klavier-sonaten. Two volumes, 1903-1905.
J. S. Shedlock.—The Pianoforte Sonata. London, Methuen, 1900.
Charles Czerny.—Pianoforte School (part 4, chapters 2 and 3).
Theodor Helm.—Beethoven's Streichquartette. 1885.
H. de Curzon.—Les lieder et airs detaches de Beethoven, 1906.
Otto Jahn.—Leonore. Klavierauszug mit Text, nach der zweiten Bearbeitung, 1852.
Dr. Erich Prieger.—Fidelio. Klavierauszug mit Text, nach der ersten Bearbeitung, 1906.
Wilhelm Weber.—Beethoven's Missa Solemnis, 1897.
Mariam Tenger.—Beethoven's Unsterbliche Geliebte, 1890. The historical value of this book has been frequently contested. Mariam Tenger was the confidential friend of Theresa in her last years. It is very likely that Theresa, then aged, may involuntarily have idealised her remembrances; but the foundation of the story appears reliable.