(a) Except as provided in (d) of this Section, any ordinance may be subject to a referendum on such ordinance as follows:
1. If such ordinance is not an emergency measure, the filing of such petition shall suspend the effective date of the ordinance until an election shall have been held as petitioned. If such ordinance is an emergency measure, it shall go into effect at once, subject to repeal by an adverse majority at the election.
2. The number of qualified voters required to sign the petition shall be a number more than 20% of the average number of voters who voted at the four regular municipal elections prior to publication of the ordinance or more than 20% of the number of voters who voted at the regular municipal election prior to publication of the ordinance, whichever is the greater.
3. Before any signatures are affixed thereon, the form of such petition must be approved by the City Clerk as provided by law.
4. No such petition or any part thereof, may be filed more than thirty-five days after publication of the ordinance.
5. An election on the issue must be held within ninety days after the date of filing the petition.
(b) At such election the ballot shall contain the text of the measure in question and below the same the phrases: "For the Above Measure" and "Against the Above Measure" followed by spaces for marking with a cross or a check the phrase desired.
(c) If a majority of the votes cast are against the measure, it shall be of no effect. If a majority of the votes cast be not against the measure, it shall go into effect forthwith.
(d) The referendum procedure of this Section shall not be available for:
1. Any ordinance authorizing bonds or other obligations where such ordinance, bonds or other obligations appropriately have been approved at an election in the city;
2. Any ordinance levying or otherwise relating to special assessments; or
3. Any ordinance which imposes, levies, increases or otherwise amends rates, tolls, fees and charges for services rendered by any municipal utility or any municipal revenue producing project if bonds or other obligations payable from the designated source are then outstanding.