Check the free white pages in each state for Oats..
Write to the public library archives / geneology of towns lived , born in, died in. Every state has info online free.cemeteries, wills, census, etc.. Ask for all info they have. For a small fee you get alot. Census, land records, wills, marriages, obits, cemeteries. They are on line for researchers of each state and county also. Ordering the death certificates on any one tells parents, where born, where buried.