In my experience those resources have some material computerized but not all material. Mississippi state supreme court law is likely not completely electronic yet.
Lexis covers it (according to their website):
Mississippi Supreme Court from 1818
Court of Appeals from December 1995
Sartin v. Barlow ex rel. Smith, 196 Miss. 159, 16 So. 2d 372, 377 (1944)
Anyone have an account?