This bibliography - intended to be as complete as possible - provides information on written material in 22 languages about "muwassa?" and "zajal" (poetical strophic forms in al-Andalus during the Middle Ages) and the "kharja" (final segment of "muwassa?" and some "zajals"), and about their popularity in East and West.

Henk Heijkoop, B.A. in History, University of Groningen, graduate pianist, director of two music schools (1962-1998), conductor, composer, and independent researcher in Hispano-Arabic culture. He has published on a variety of musical subjects.
Otto Zwartjes, Ph.D. (1995) University of Nijmegen, has published extensively on the kharjas and has been Full Professor of Spanish Language and Linguistics at the University of Oslo since 1999. Currently he is leader of the "Oslo Project on Missionary Linguistics" (OsProMil) which focuses on Spanish and Portuguese descriptions of non-Indoeuropean languages during the colonial period.