The death certificate for Anna E. Kellar who died in Feb 1940 in Henry Co, MO and was buried in California, MO is the Emma Baldwin Roberts Keller you are looking for. Don't know why name on d/c is Anna E., but don't ever let that discourage you because mistakes were often made. The informant on the certificate, Mrs. Herman Henry, is Lillie Roberts Henry. The 1900 census lists Charles and Emma Keller's family and there is a 16 year old daughter, Lillie Roberts. This is how I was able to find Lillie's death certificate.
Lillie May Henry's death certificate lists her parents as Joush Roberts and Emma Baldwin. I wonder about the spelling of Joush Roberts, wonder if it might be Josh. Lillie May Roberts Henry died in Moniteau Co MO on 16 Nov 1952 and she is also buried in California, MO.
Emma's d/c stated she was born in Ohio in 1854.
The 1860 census lists a 4 yr old Emma C. Baldwin, born in Ohio, parents were: Benjamin Baldwin and Elizabeth Baldwin.
This family was living in Cooper Co, MO. The same family was also listed on the 1870 census, also in Cooper Co, MO.
This is undoubtly the Emma you are looking for.
Hope this information helps you.