Marriage certificate. The relevant entry is on the top of the right column.

Extract from 1920 census of Atlanta, Georgia.
The census indicates (starting at line 59) that on January 8, 1920 the Burnett houseold consisted of Otis C. (head, age 29), Maud (wife, age 29), Newell (son, age 7), Georgia (daughter, age 4), Otis C. Jr. (son, age 2) and Willie May (daughter, age 9 months).

Extract from 1930 census of Atlanta, Georgia.
The census indicates (starting at line 27) that on April 18, 1930 the Burnett houseold consisted of Otis C. (head, age 39), Maud (wife, age 39), Newell (son, age 17), Georgia (daughter, age 14), Otis Jr. (son, age 13), Willie M. (daughter, age 11) and Gus (son, age 8).

Extract from 1940 census of Atlanta, Georgia.
The census indicates (starting at line 41) that in 1940 the Burnett household consisted of Otis C. (head, age 49), Maud (wife, age 49), Alfred N. (son, age 28), Georgia F. (daughter, age 24), Otis C. (son, age 23), Willie May (daughter, age 20) and Augustus B. (son, age 18).

Cemetery record from Greenwood Cemetery in Atlanta, Georgia for Maude Greenslade, Otis Cicero Burnett and Georgia F. Burnett. JoAnn Edgerton's name is written in pencil, which means a spot in the gravesite was reserved for her. However, she was interred in Winkenhofer Pine Ridge Memorial Park in Kennesaw, Georgia.