29 CFR 1206.3 - Age of authorization cards.
Authorizations must be signed and dated in the employee's own handwriting or witnessed mark. No authorizations will be accepted by the National Mediation Board in any employee representation dispute which bear a date prior to one year before the date of the application for the investigation of such dispute.
Title 29 published on 2013-07-01
no entries appear in the Federal Register after this date.