A couple of our members were discussing Missouri Death Certificates online as well as how to order certified copies. Here are some starter links:
http://sos.mo.gov/archives/resources/deathcertificates/ – state site contains 1910-1961 and links for other resources. – via Shirley C.
http://www.missouri-deathcertificates.com/ – order official Missouri vital records copies directly from the state.