Each director before entering upon his official duties shall take and subscribe to an oath before an officer authorized to administer oaths, that he will support the Constitutions of the United States and the State of Nebraska, will honestly, faithfully and impartially perform the duties of his office and will not be interested directly or indirectly in any contract let by said district. The oath shall be filed in the office of the department in the original case.
Neb. Rev. Stat. §§ 46-536