Md. Code, State Personnel and Pensions § 27–301

A member is entitled to service credit:

(1) for service as a member;

(2) regained under § 27–302 of this subtitle by a member who redeposits accumulated contributions previously withdrawn;

(3) for prior service as provided in § 27–303 of this subtitle; or

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