BAGLEY ET AL: 'Creating Reusable Well-Structured PDF as a Sequence of Component Object Graphic (COG) Elements', PROCEEDINGS OF THE 2003 ACM SYMPOSIUM ON DOCUMENT ENGINEERING. DOCENG 2003. GRENOBLE, FRANCE, NOV. 20 - 22, 2003; [ACM SYMPOSIUM ON DOCUMENT ENGINEERING], NEW YORK, NY : ACM, US, 22 November 2003 (2003-11-22), XP002459862, ISBN: 978-1-58113-724-8