General information on German copyright law
In Germany, the copyright expires 70 years after the death of the copyright owner (UrhG § 64). In the case of shared copyrights, the expiration date is 70 years after the death of the last surviving copyright owner; for anonymous works, 70 years after their first publication. After this period, the previously copyrighted works become public domain and may be used without prior permission. If the copyright owner deceased less than 70 years ago, the copyright passes to his/her heirs. In this case, a person wishing to use the copyrighted works would need to get permission from the heirs.
In all other cases, the person wishing to use the copyrighted works must ask the copyright owner for permission. Legal certainty regarding possible exceptions for the use of copyrighted works in the academic realm is subject to the outcome of the so-called "Dritter Korb" in German copyright law.
Please click here for the full text of German copyright law.
Further information on copyright in the sciences and academia can be found here.
Information on using images from DAI publication is available here.