This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Zentralbibliothek Zrich Hans Conrad Escher von der Linth .tif de Hans Conrad Escher von der Linth um institution Zentralbibliothek Zrich object history credit line accession number Public domain File ZentralbibliothekZrichHansConradEschervonderLinth ZentralbibliothekZrich MediacontributedbyZentralbibliothekZrich original picture