1107.1 What Is a Serial?
For purposes of this group registration option, a serial is defined as a work that is issued or intended to be issued on an established schedule in successive parts bearing numerical or chronological designations that are intended to be continued indefinitely. Examples include periodicals (including newspapers), annuals, the journals and proceedings of societies, and other similar works. See 37 C.F.R. § 202.3 (B) (1)(v).