Visually minimalist macOS PDF reader supporting Copying as Full Citation:
To Enable Full Citation Copying
To enable full-citation copying, open the PDF Reader and copy theBibTex or DOI of the PDF, which you can find either on the download page or in the document, and paste it into the document. The citation information will now be appended to the end of the document. That’s it, you can now copy as full citation to Author.
The interaction shown above is simplified if you install the Google Chrome Visual-Meta Extension: Video demo The Visual-Meta Extension for Chrome automatically finds the BibTeX Export Format for citations when you download a PDF documents from the a website (ACM Digital Library is the first fully tested site) and appends the BibTeX to the PDF as a Visual-Meta element. But that's not the exciting part:
You can then use Reader for macOS and copy any text from your PDF and paste into Author as a full citation.
This is a usable and useful demonstration of the Visual-Meta approach. Future updates aim to support more download sites.