The C2D is an academic research centre dedicated to the study of direct democracy around the world. This site has a database with information on direct democracy institutions such as the referendum and the initiative as well as their use in popular votes.
The CCP has collected and analyzed thousands of constitutional texts and made that data publicly available. Together with Google Ideas, the CCP built and launched Constitute, a website that contains a richly indexed set of texts for nearly every national constitution in the world.
ConstitutionNet is a project created to support legislators, constitutional lawyers and other constitutional practitioners in finding useful and relevant information, sharing knowledge and building a community of best practice.