37 C.F.R. § 4.5 Notice by publication.
Title 37 - Patents, Trademarks, and Copyrights
If the copy of the complaint that is mailed to the invention promoter is returned undelivered, then the USPTO will primarily publish a Notice of Complaint Received on the USPTO's Internet home page at http://www.uspto.gov. Only where the USPTO's Web site is unavailable for publication will the USPTO publish the Notice of Complaint in the Official Gazette and/or the [68 FR 9553, Feb. 28, 2003]
Title 37: Patents, Trademarks, and Copyrights
PART 4—COMPLAINTS REGARDING INVENTION PROMOTERS
§ 4.5 Notice by publication.

