Publication (Symantec Security Response): The Rise of PDF Malware by Karthik Selvaraj and Nino Fred Gutierrez

This is a good overview of the current PDF malware (up to September 2010)
Download paper

This appendix has a very nice chart of what is what when it comes to PDF these days (Click to enlarge)

Hacker Magazine (Xakep - Haker #10 2009) in Russian

Links updated: Jan 18, 2023

Hacker Magazine (Xakep - Haker #10 2009)
Download pdf in Russian