The initiative and referendum are reserved by this Charter to the people of Blue Ash to be exercised as prescribed in this Charter. Electors qualified by registration and otherwise to vote in Blue Ash, and equal in number to not less than one-fifth (1/5) of the number of those who voted in the preceding general election, may by an initiative petition propose to Council the passage of an ordinance or resolution set forth therein, or by a referendum petition propose the repeal of any measures passed within forty (40) days by Council, except as otherwise prescribed in this Charter.