37 C.F.R. § 2.194 Identification of trademark application or registration.
Title 37 - Patents, Trademarks, and Copyrights
(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.
Title 37: Patents, Trademarks, and Copyrights
PART 2—RULES OF PRACTICE IN TRADEMARK CASES
General Information and Correspondence in Trademark Cases
§ 2.194 Identification of trademark application or registration.
