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FamilySearch: Bernhard Otto Kellner. https://www.familysearch.org/ark:/61903/3:1:3Q9M-C912-892Y-N?view=index&personArk=/ark:/61903/1:1:DWH2-4L2M&action=view&cc=3732502 AND https://ancestors.familysearch.org/en/M4KC-2G2/dr-bernhard-otto-kellner-1836-1918
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