1. According to the Report of the Kiev Civil Governor about the Christian Woman Maria Guleva, who Converted to Jewish Law and Later Married the Jew Gesem Kushnir, 1825, Fund 1284, Anagraph 195, Case 53, The Russian State Historical Archive,1825
2. Life in a Jewish Shtetl of the Late 19th–Early 20th Century
https://berkovich-zametki.com/2009/Starina/Nomer2/Bejzer1.php
3. The Emergence of Eurafrican Jews;Ben-Ur,2020
4. Judaizing in the Seventeenth Century: Francis Mercury van Helmont and Johann Peter Späth (Moses Germanus);Coudert,2004
5. The Unknown Investigation of the Kazan Judaizer Sect;Feldman,1999