Roksana,
You wouldn't happen to be doing this project for a class with Anthony McCann would you? If you are, tell him that Rev from Santa Barbara says hello. If not, you should look into his work. He has done a lot on the subject of copyright and traditional music, primarily relating to Irish music. He was teaching at University of Sheffield, but I don't think he's there any longer.
His website is

www.anthonymccann.com

and his ongoing project on this topic is called "beyond the commons"

Revell Carr