Md. Code, Education § 6–505

(a) Employee organizations recognized by the public school employer as the exclusive representative of all public school employees in a specified unit on July 1, 1978, shall continue to be the exclusive representative subject to Title 22, Subtitle 4 of the State Government Article.

(b) Any collective negotiation agreement that has been entered into by an exclusive representative and a public employer as of July 1, 1978, shall continue in effect for the term of the agreement.