Miriam Frenkel, The Compassionate and Benevolent: The Leading Elite in the Jewish Community of Alexandria in the Middle Ages (in Hebrew) (Jerusalem: Ben-Zvi Institute for the Study of Jewish Communities in the East, 2006).
for edition see
Doc. #76, pp. 552-556
Moshe Gil and Ezra Fleischer, Yehuda Ha-Levi and His Circle (in Hebrew) (Jerusalem: ha-Igud ha-ʻolami le-madaʻe ha-Yahadut, 2001).