Section 267.335 - Authority to issue revenue bonds; interest-bearing warrants(1) In addition to the authority to issue general obligation bonds, after a vote of the people, a district may issue and sell revenue bonds and pledge as security therefor all or any part of the unobligated net revenue of the district. Revenue bonds shall be issued in the same manner and form as are general obligation bonds of the district but they shall not be subject to the percentage limitation provided by ORS 267.330 applicable to issuance of general obligation bonds and shall not be a lien upon any property within the limits of the district. Such bonds shall be payable, both as to principal and interest, solely from the net revenues of the district remaining after payment of obligations having a priority and payment of all expenses of operation and maintenance of the district, including any taxes levied thereafter against the district. All revenue bonds shall contain a clause reciting that both the principal and interest are payable solely from net revenues of the district remaining after paying such obligations and expenses.(2) In lieu of issuing bonds secured by unobligated net revenue under subsection (1) of this section, the treasurer, when authorized by the board, may execute and issue interest-bearing warrants drawn against funds created by and for operation and maintenance of the mass transit system in excess of current cash on hand, but not in an amount exceeding one-half of the estimated annual gross revenue for operation of the mass transit system for the next ensuing year.