| Source of Information |
| Subcategories |
| Committee for Sustainable Development of United Nations (CSD) | Council of EU | Environmental institutions |
| European Commission (EC) | European Council | European Environmental Agency |
| European Environmental NGO's | European Parliament | European Union (EU) |
| Governmental organizations | High School Education | Independent Organizations |
| Institutions | International Environmental NGO's | International Organizations |
| Local governments | Magazines | Ministries |
| Museums | National Center for Environmental Information | National Environmental NGO's |
| Newspapers | Non profit organizations | Other sources of information |
| Primary education | Private Companies | Publishing Houses |
| Research Centers | Research Institutes | Stakeholders |
| State owned companies | Universities - Technical Universities | Various authorities |