That "Seymour" reference would be Seymour, William. The Civil War Memoirs of Captain William Seymour: Reminiscences of a Louisiana Tiger. Ed. Terry L. Jones. Baton Rouge & London: Louisiana State University Press, 1991. I would suspect you could get a copy pretty easily through interlibrary loan. If you wanted to buy a copy, Bookfinder.com is pretty good about having books like this, although I haven't looked there for this particular book.