Any bonds, notes, warrants and other evidences of indebtedness issued or incurred by the district shall be signed as provided in the section of this part applicable thereto or as provided in any other law applicable thereto; provided, however, that if the particular section or law does not prescribe the method of such execution, the method provided for bonds of the district shall apply so far as applicable. All other contracts of the district shall be executed on behalf of the district by the general manager; provided, however, that the board may, by resolution, fix any other method of executing such contracts.