35 Pa. Stat. § 691.212
When a municipality shall issue any non-debt revenue bonds, the corporate authorities thereof shall sell the same to the highest bidder after public notice by advertisement once a week for three weeks, in at least one newspaper of general circulation, published in the municipality or the county in which the municipality is situate. Where bonds shall be advertised for sale as herein provided, and no bids shall have been received, then it shall be lawful for such municipality to sell the same at private sale for not less than par and accrued interest.
All such bonds shall be payable in not more than thirty years from the date of their issue, shall be issued in series payable in equal annual installments, and shall bear interest at a rate not exceeding six per centum per annum.
35 P.S. § 691.212