37 CFR § 2.194 - Identification of trademark application or registration.
(a) No correspondence relating to a trademark application should be filed prior to receipt of the application serial number.
(b) (1) A letter about a trademark application should identify the serial number, the name of the applicant, and the mark.
(2) A letter about a registered trademark should identify the registration number, the name of the registrant, and the mark.
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