1. Patenting software vs. Free Software, What should the European Union do?;The patentability of software programs, by Reinier Bakels and P. Bernt Hugenholtz,2002
2. UK Patent Office
3. International Chamber of Commerce, Current and Emerging Issues Relating to Specific Intellectual Property rights;The TRIPs agreement
4. Patentability Criteria in Different Countries
5. Evaluate Patentability of your Invention;Umakant Mishra;TRIZsite Journal,2006