Hospital district; bonds; issuance; approval of electors.

No bonds shall be issued under the provisions of sections 23-3554 to 23-3572 until the question has been submitted to the qualified electors of the district, and a majority of all the qualified electors voting on the question shall have voted in favor of issuing the same, at a special election called for that purpose, upon notice given by the board of directors at least twenty days prior to such election.