1. Rubber stamps: revisited the examination of defects on a laser engraved reproduction of a stamp impression;Seiden H;Int J Forensic Doc Exam,1998
2. Rubber Stamps. Manufacture and Identification
3. The individuality of rubber stamps
4. SWGDOC.Standard for examination of rubber stamp impressions.http://www.swgdoc.org/index.php/standards/published-standards(accessed November 22 2019).