Hi, I was playing around with strange records (one with no setting for control number) and managed to tickle this-- 703156da (Katrin Fischer 2010-11-24 11:35:43 -0500 1266) sub GetMarcControlnumber { 703156da (Katrin Fischer 2010-11-24 11:35:43 -0500 1267) my ( $record, $marcflavour ) = @_; 703156da (Katrin Fischer 2010-11-24 11:35:43 -0500 1268) my $controlnumber = ""; 703156da (Katrin Fischer 2010-11-24 11:35:43 -0500 1269) # Control number or Record identifier are the same field in MARC21 and UNIMARC 703156da (Katrin Fischer 2010-11-24 11:35:43 -0500 1270) # Keep $marcflavour for possible later use 703156da (Katrin Fischer 2010-11-24 11:35:43 -0500 1271) if ($marcflavour eq "MARC21" || $marcflavour eq "UNIMARC") { 703156da (Katrin Fischer 2010-11-24 11:35:43 -0500 1272) $controlnumber = $record->field('001')->data(); 703156da (Katrin Fischer 2010-11-24 11:35:43 -0500 1273) } 703156da (Katrin Fischer 2010-11-24 11:35:43 -0500 1274) } which causes-- Can't call method "data" on an undefined value at /home/reedpetone/koha/dev/koha/C4/Biblio.pm line 1272. when I do this-- http://koha/cgi-bin/koha/opac-detail.pl?biblionumber=2 ------- Since it's a small and recent item, advice on IRC was to just send this to the list. -reed