Baker v. State, 519 S.W.2d 437 (Tex.Crim.App. 1975).

Tennery v. State, 680 S.W.2d 629 (Tex.App.—Corpus Christi 1984, pet. ref’d).

Burden of proof is on defendant to show by sworn affidavit plus testimony (from some source) that he is eligible for probation.