Legally binding is only the full legalcode. For a free usage I recommend to respect the following licence conditions:
1. Provide a copy of, or the URI for, the applicable license: https://creativecommons.org/licenses/by-sa/3.0/de/legalcode,
2. my name as given above,
3. the title of the work,
4. in the case of an adaptation, a credit identifying the use of the work in the adaptation.
This license and the rights granted hereunder will terminate automatically upon any breach by you of the terms of this license. In this case the author reserves to demand declaration to cease and desist, and compensation (according to the MFM fee references currently in force).
Any of the above conditions can be waived if you get permission from the copyright holder. If you have questions or wish differing conditions or a higher resolution, please contact me through: eMail via Wikipedia or my discussion page