The Wall

No, my PhD is not about Pink Floyd's legendary double album from 1979, neither have I hit the wall (yet). The wall in question is a result of me trying to get an oversight of the Norwegian classical female singers from the early 20th century and their teachers, using good old detective methods, including photos and red string. In the bottom two columns are singers that were recorded in Norway between 1900 and 1920, and above them are their teachers and the teachers' teachers. I constantly add new details to the wall, and so far, J. S. Bach, G. Rossini and Edvard Grieg himself have found their place in this map of musical influences on the Norwegians. Do you spot other "celebrities"?