Returns; form, verification and authentication, time of filing

Returns shall be in such form as the department of taxation may prescribe from time to time and shall be verified by written declarations that the statements therein made are subject to the penalties prescribed in section 231-36. Corporate returns shall be authenticated by the signature of the president, vice president, treasurer, assistant treasurer, chief accounting officer, or any other officer duly authorized so to act, under the penalties prescribed by section 231-36. The fact that an individual's name is signed on the corporation return shall be prima facie evidence that the individual is authorized to sign the return on behalf of the corporation. The department may grant a reasonable extension of time for filing returns under such rules as it shall prescribe. Except as otherwise provided by statute for cases in which exceptional circumstances require additional time, including cases of persons who are outside the United States, no extension of time for filing returns shall be for more than six months in order to expedite the timely determination of tax liability and the timely remission of taxes.