Otto Volkert seems to be a family name. Here is his Uncle Otto's census with a cousin named Otto.
Uncle Otto 1940 Census
Name: Otto A Volkert
Age: 36
Estimated Birth Year: abt 1904
Gender: Male
Race: White
Birthplace: Minnesota
Marital Status: Married
Relation to Head of House: Head
Home in 1940: Minneapolis, Hennepin, Minnesota
Household Members:
Name Age
Otto A Volkert 36
Irmgard Volkert 38
Otto F Volkert 7 Cousin Otto
Robert W Volkert 3
Marie C Volkert 10/12
Charlotte Volkert 70
Adele Meyer 28
Uncle Otto death
Name: Otto A. Volkert
SSN:
Last Residence: 55412 Minneapolis, Hennepin, Minnesota, United States of America
Born: 25 Jan 1904
Died: 4 Jun 1988
State (Year) SSN issued: Minnesota (Before 1951)