Every payroll must bear a certification signed by the head of the department concerned or by other persons to whom the authority to sign such certification has been delegated. Such delegation must be made by written direction of the head of the department, and filed in the Department of Audit and Control. The certification must state that individuals to whom payment is to be made “are employed solely in and have actually performed the proper duties of the positions and employments indicated, and that the persons described therein as ‘laborers' are employed at ordinary unskilled labor only; and said payroll for the period is approved at $__ and is certified for payment from the appropriations enumerated therein, and that the persons named in said payroll, except those appointed and employed as laborers, have taken and filed the constitutional oath, in accordance with the provisions of section 62 of the Civil Service Law, and that all persons so named have complied with pertinent requirements of the Civil Service Law” (State Finance Law, sections 109, 110).