Delaware constitution
Article XV
Section 8

No member or officer of any department of the government shall be in any way interested in any contract for the furnishing of stationery, printing, paper and fuel used in the legislative and other departments of government; or for the printing, binding and distributing of the laws, journals, official reports, and all other printing and binding, and the repairing and furnishing the halls and rooms used for the meetings of the General Assembly and its committees, when such contract is awarded to or by any such member, officer or department.