Layer, Adolf; Ullrich, Hermann (2001). Demmler [Demler, Dümmler], Johann Michael. Oxford Music Online. Oxford University Press. doi:10.1093/gmo/9781561592630.article.07542.
Sources vary regarding the English pronunciation of Mozart's name. Fradkin 1996, a guide for classical music radio, strongly recommends the use of the phoneme [ts] for the letter z (thus /ˈwʊlfɡæŋˌæməˈdeɪəsˈmoʊtsɑːrt/WUULF-gang AM-ə-DAY-əs MOHT-sart), but otherwise considers English-like pronunciation fully acceptable. The German pronunciation is [ˈvɔlfɡaŋʔamaˈdeːʊsˈmoːtsaʁt]ⓘ. Fradkin, Robert A (1996). The Well-Tempered Announcer: A Pronunciation Guide to Classical Music. Bloomington: Indiana University Press. ISBN978-0-253-21064-7.
See Barry 2000 for detailed discussion of the influence of Opus 33 on the "Haydn" quartets. Barry, Barbara R. (2000). The Philosopher's Stone: Essays in the Transformation of Musical Structure. Hillsdale, New York: Pendragon Press. ISBN978-1-57647-010-7. OCLC466918491.
Haberl 2006, pp. 215–255. Haberl, Dieter (2006). "Beethovens erste Reise nach Wien: die Datierung seiner Schülerreise zu W.A. Mozart". Neues Musikwissenschaftliches Jahrbuch (in German) (14). OCLC634798176.