It includes information about Slayback's capture and escape from the Federals. References include the book Shelby and His Men or the War in the West by John Newman Edwards.
A matter of honor lead to his death at the hands of former Union officer, an Editor of Pulitzer's St. Louis Post Dispatch. According to the above site, a pistol was planted in the COL Slayback's coat to help the editor gain an acquittal on the assertion of self defense. A google book search disclosed at the following site:
that COL Slayback's poetry and prose were published in a Memorial Volume after his death.
The following US GenWeb site has a transcription of COL Slayback's Memorial Day Speech at the National Cemetery at the Jefferson Barracks in 1873:
I hope that this gives you a place to start. Best wishes.