About She'erit ben Sa'adya al-Fayyūmi
In a letter written in 928, Saʿadya mentions his older son, She'erit, but not Dosa. Presumably he was born later, probably around 935, and thus was only a boy when his father died in 942. Dosa was at least seventy-five when he became head of the academy after the death of Samuel ben Ḥophni Gaon in 1012, but he had long held a privileged status in the academy and had been given half of the contributions it received. In 953, She'erit and Dosa compiled a list of their father's books. According to the Sefer ha-Qabbala of Ibn Da'ud, Dosa also wrote a biography of his father in an epistle to Ḥasday ibn Shapruṭ, "The Story of Rav Saʿadya and the Benefits He Did for Israel” (Divre Rav Saʿadya veha-ṭovot she-ʿasa le-ʿam Yisra’el)
Only a few of Dosa's responsa survive. They reflect the new halakhic spirit of his father and Ben Ḥophni. In one of them he defends Hay (Hayya) Gaon against Samuel Ibn Naghrella's criticism of one of his talmudic interpretations. According to his own testimony in another responsum, he had taken an oath sixty years earlier to refrain from eating bread, probably as an act of asceticism. Dosa died in year 1018.
Gil, Moshe. In the Kingdom of Ishmael (Jerusalem: Mosad Bialik, 1997), pp. 369–370 [Hebrew].
——–. Jews in Islamic Countries in the Middle Ages, trans. David Strassler (Leiden: Brill, 2004).
Mann, Jacob. Texts and studies in Jewish History and Literature, vol. 1 (Cincinnati: Hebrew Union College Press, 1931), p. 153.
Margalioth, Mordechai. Hilkhot ha-Nagid (Jerusalem: Qeren Yehuda ve-Mini Epstein, 1962), pp. 31–34.
Poznanski, Samuel. “Rav Dosa b. Rav Saʿadya Ga’on,” Ha-Goren 6 (1905): 41–64.
Citation Roni Shweka. " Dosa ben Saʿadya Gaon." Encyclopedia of Jews in the Islamic World. Executive Editor Norman A. Stillman. Brill Online , 2013. Reference. Jim Harlow. 25 January 2013 <http://referenceworks.brillonline.com/entries/encyclopedia-of-jews-in-the-islamic-world/dosa-ben-saadya-gaon-SIM_0006740>