List of Mennonite villages in Russia: http://www.blackseagr.org/pdfs/konrad/Mennonite%20Villages%20in%20Russia.pdf
Resources for Mennonites in Russia: http://www.mennonitegenealogy.com/russia/.
Mennonite Family History. [Family History Library book No. ] https://familysearch.org/search/catalog/55577?availability=Family%20History%20Library.
Genealogical Registry and Database of Mennonite Ancestry. Grandmaonline.org. This is a subscription site.