The board shall determine and provide in the resolution laying the assessments, adopted in accordance with section ten of this article, the method of financing the cost of a project, for the cost of which assessments are levied as in this article provided, and such method may include the receipt of gifts, grants from any governmental agency or appropriations from the county or municipality in which the assessment district is located, or borrowing funds from any person or governmental agency, or any combination thereof: Provided, That any funds borrowed by an assessment district, including any interest accruing thereon, shall be repaid solely from the proceeds of the assessment certificates issued pursuant to section fifteen of this article and from the assessments evidenced thereby.