Maryland Code, Local Government § 4-412

(i) a referendum of the qualified voters of the municipality if the petition for referendum was presented by the residents of the municipality;

(ii) subject to § 4-413 of this subtitle, a referendum of the registered voters who are residents in the area to be annexed if the petition for referendum was presented by the residents of the area to be annexed; or

(iii) separate referendums of the voters specified in items (i) and (ii) of this paragraph if a petition for referendum was presented by the residents of the municipality and the residents in the area to be annexed.

(2)(i) If a referendum is conducted for both the residents of the municipality and the residents in the area to be annexed, the votes cast for the two referendums shall be tabulated separately to show the votes cast in the municipality and the area to be annexed.

(ii) If in both referendums a majority of the persons voting on the annexation resolution vote for the resolution, the resolution takes effect on the 14th day after the referendum.

(iii) If two referendums are held, the annexation resolution is void unless a majority in both referendums vote for the resolution.