If you are doing Missouri Research you definately need to check out the Missouri Digital Heritage website. They have scanned death certificates for 1910-1957. The file seems pretty complete, out of the 14 people I searched for that died during that time there were only 2 that I couldn't find and for one I don't have they exact date of death and could actually have been in 1909. The other one is a common name so I will just need to research a bit more. But it is a great website, make sure if you are doing Missouri Research you check it out. Here's the link:
Let me know what you think.