(14)???Signatures required. 71.80(14)(a)(a) Except as otherwise provided by par. (b), sub. (20) and ss. 71.03 (2) (b) and (c), 71.13 (1), 71.20 (1), 71.21 (1) and 71.24 (4), any return, statement or other document required to be made under this chapter shall be signed in accordance with rules promulgated by the department.