Оригинал: Schradieck, Henry. Lifschey, Samuel Publisher. School of Violin Technics. Viola transcription. Schradieck, Henry. Viola. New York.
Превод: Schradieck, Хенри. Училище на Violin Technics. Schradieck, Хенри. Виолетов. G. Schirmer, 1900 Copyright.