Linksammlung

PDF Spec:

• Adobe PDF Spec PDF Reference
  
• PDF Association www.pdfa.org

PDF Generation:

• ITEXT itext JAVA
  AFFERO GENERAL PUBLIC LICENSE (AGPL)
  
• TCPDF TCPDF PHP
  
• Foxit Foxit PDF Toolkit
  
• GhostScript GhostScript
  

PDF Reader/Editor:

• PDFium PDFium Google / Foxit C++ OpenSource
  
• PDF4QT PD4QT
  
• Xpdf Xpdf
  

PDF Validation:

• Validation verapdf

Freie Programme:

• Sumatra Sumatra PDF Reader / OpenSource
  
• Adobe Reader Adobe Reader
  
• PDF StreamDumper PDF StreamDumper
  

Diverse:

• ISO 32000-2, the PDF 2.0 specification — is now available at no cost
  
• Wikipedia PDF
  
• List_of_PDF_software
  
• Adobe PDF Technology - Center
  
• PDFLabs
  
• Apache PDF box