Along the same lines, don't miss "Organization and Status of Missouri Troops, Union and Confederate, in Service During the Civil War" published in 1902. On the above site, scroll down to "United States. Record and Pension Office."
The 1863 AG's report is also online here: http://digital.library.umsystem.edu/cgi/t/text/text-idx?sid=de397cb5292a5eb72e4a46e588bc8e28&c=umlib&cc=umlib&tpl=browse.tpl
Again, scroll down to "Missouri. Office of the Adjutant General."