Hello, sorry for posting in this section but I followed a music licence related-post I found through google. I am a PhD student and I am writing a publication on classical music. I'd like to show in my publication 4 musical fragments taken from 4 different musical pieces of 4 different authors, two of whom from the beginning of the twentieth century and the remaining from the mid-century. I would like to ask if I have to license the material and, if yes, how or where I can find more detailed information about. Luca