In order to handle authority limits, get_link should always end with:
return $self->SUPER::_handle_auth_limit($authid), $fuzzy;
+B<update_cache ($heading, $authid)> - updates internal linker cache for
+$heading with $authid of a new created authotiry record
+
B<flip_heading ($field)> - return a MARC::Field object with the heading flipped
to the preferred form.