This looks like an excellent project started in 2011. The text below on licensing is a good example of clarity.
# Reusing historical public domain content As our name suggests, our project is focused on showcasing works that are in the public domain and so are free to reuse for any purpose, even commercially. If you want to reuse these works, there are two key factors to consider. The first is that, while we try to mostly feature works in the public domain worldwide, some may not be public domain in all countries. (Read more about variation in copyright terms). The second is that, while the underlying work itself may be free from copyright, the digital copy we feature can sometimes be subject to claims of additional copyright or restrictions on reuse. (Read more about rights on digital copies). For the historical content found in the Collections part of our site, we communicate to the best of our knowledge the rights status of both the underlying work and the digital copy of this work. We provide this information based on a basic knowledge of copyright law and what is communicated by the source institution — it is strictly meant as a guideline and it should not be taken as legal advice. The historical material featured in our Essays series is not accompanied by rights labels, just links to the original source. If reusing material for commercial purposes — from either our Collections or Essays section — it might be a good idea to further investigate any usage restrictions by clicking through to the source using the links provided. Images we feature on the site will often have been edited by our team in an attempt to improve their aesthetic presentation. However, we assert no additional rights to these edited versions. If reusing public domain material from our site then you are under no obligation to mention us, but we would really appreciate a mention and link back if practicable. Every credit and link back to our site helps grow our audience and continue the project. If you are able, please do also consider donating to the project.
# See
- Coughs and Sneezes
- Maria Sibylla Merian
- https://publicdomainreview.org/reusing-material/
- publicdomainreview.org 