Neb. Rev. Stat. § 72-411

All trustees comprising the board shall take an oath in writing in such form as the county attorney of the county shall provide and approve, faithfully to execute the duties and trusts committed to their care and management, and to dispose of the funds and income and corpus of such trusts in conformity with sections 72-407 to 72-420 and the wishes expressed in the instruments creating the trust estates.