'SL::DB::PurchaseInvoice' => sub { $_[0]->invnumber },
'SL::DB::RequirementSpec' => sub { $_[0]->id },
'SL::DB::Letter' => sub { $_[0]->letternumber },
'SL::DB::PurchaseInvoice' => sub { $_[0]->invnumber },
'SL::DB::RequirementSpec' => sub { $_[0]->id },
'SL::DB::Letter' => sub { $_[0]->letternumber },