+L<FS::part_pkg> - Package definition class
+
+L<FS::part_pkg_option> - Package definition option class
+
+L<FS::pkg_svc> - Class linking package definitions (see L<FS::part_pkg>) with
+service definitions (see L<FS::part_svc>)
+
+L<FS::rate> - Rate plans for call billing