Erik Skydsgaard, J. (1991). Jørgen Bæk Simonsen: Studies in the Genesis and Early Development of the Caliphal Taxation System. Kbh., Akademisk Forlag, 1988, 213 sider. Historisk Tidsskrift, 15. Hentet fra https://tidsskrift.dk/historisktidsskrift/article/view/53308