This culture is very roughly described as maqam music shaped by Western influence. The music is modal with scales like phrygian (kurd) or double-harmonic major (hijazkar). Yes it's in 12-tone temperament, as the instruments are fretted strings, brass, accordion. Sometimes droning bases or major/minor triads are used as harmony.
- Matthew James Kay. A Return to Brotherhood: Nationalism, Globalization and The Negotiation of Identity in Romani Brass Band Music in Serbia - The author describes his visits to a Guča festival and to a Romani village to interview musicians
- Risto Pekka Pennanen. The Development of Chordal Harmony in Greek Rebetika and Laika Music, 1930s to 1960s
- Hans Baken. Folk Music from Bulgaria, Fake Book
- Maqam: Historical Traces and Present Practice in Southern European Music Traditions. Edited by Jürgen Elsner, Gisa Jähnichen and Jasmina Talam