Mo. Rev. Stat. § 116.260
The secretary of state shall designate in what newspaper or newspapers in each county the text of statewide ballot measures shall be published. If possible, each shall be published once a week for two consecutive weeks in two newspapers of different political faiths in each county, the last publication to be not more than thirty or less than fifteen days next preceding the election. If there is but one newspaper in any county, publication for four consecutive weeks shall be made, the first publication to be not less than twenty-eight days next preceding the election. If there are two or more newspapers in a county, none of which is of different political faiths from another, the statewide ballot measures shall be published once a week for two consecutive weeks in any two newspapers in the county with the last publication not more than thirty or less than fifteen days next preceding the election.
§ 116.260, RSMo