No account or statement of indebtedness for any personal service, work or labor or for property, materials or supplies performed for, or furnished to, any agency shall be valid unless made out on a form prescribed by the Director of the Office of Management and Budget and conforming to § 6515 of this title.

32 Del. Laws, c. 30, § 2; Code 1935, § 426; 29 Del. C. 1953, § 6513; 54 Del. Laws, c. 39, § 5; 57 Del. Laws, c. 741, § 1E; 75 Del. Laws, c. 88, § 21(13)