Permission to use pictures
The use of images for teachers, pupils and students for worksheets or presentations (non-commercial) is permitted.
The following applies:
1. For presentations: A reference to the source at the end of the presentation is sufficient.
2. For worksheets: No reference required!
3. For teachers at universities: If students have to pay for the courses, the use of the materials is not permitted!
4. For publishers: If interested, just contact me.
If you want to save a picture, just click on it with the right-mouse-button and choose "save picture" or "download picture"