Maryland Code, State Personnel and Pensions § 25-303

(1) for employment as a member;

(2) regained under § 25-304 of this subtitle by a member who redeposits accumulated contributions previously withdrawn;

(3) transferred from a retirement or pension system under Title 37 of this article or Title 31, Subtitle 1 of this article;

(4) for military service as provided in Title 38 of this article;

(5) purchased under this subtitle; or

(6) transferred from the Employees' Pension System under § 25-306.1 of this subtitle.