This project uses only materials which are based on 

• Copyleft
• Public domain
• Creative commons  
• Free Royalities licenses  
• self created materials.

If we find any material which is not based in one of this three categories will be deleted as soon as discovered.

Places where this materials can be found : 

• --> Wikipedia
• --> Autoring tools
• --> freepik.com (some of them are free to use) 
• --> pixabay.com/ (some of them are free to use) 
• --> free-images.com 

Please be careful with this subject.