Missouri Death Certificates, 1910-1956 online
This is a very useful site if you are searching for ancestors who died in Missouri between 1910 and 1956.
http://www.sos.mo.gov./archives/resources/deathcertificates/http://www.sos.mo.gov./archives/resources/deathcertificates/
I found someone in about 2 minutes that has been eluding me for more than 10 years.