Del. Code tit. 9, § 743

All ordinances, orders and resolutions of the governing board of any park district and the date of the publication thereof may be proved by the certificate of its secretary under the seal of the district. When printed in book or pamphlet form purporting to be published by the governing board such book or pamphlet shall be received as evidence of the passage and legal publication of such ordinances, orders, and resolutions as of the dates mentioned in such publication in all courts or places without further proof.