Hello,
this is how i use Calibre in addition to the firefox plugin
Zotero and the freeware program
Zettelkasten deutsch /
Zettelkasten english:
I uses Calibre to store my pdf / epub books to sync with my reader. One time a week I create a catalogue of my new books in Calibre:
Convert Books > Create catalog ...
This catalogue is stored in .bib-format with UTF-8 and "strict".
I can import this catalogue
a) in Zotero, where all my other (non-electronic) books are stored and
b) also in Zettelkasten. In this case I use the "Zotero" filter in Zettelkasten.
In Zotero I use the function "Attach Link to File" and I use the stored ebook in Calibre, so that I have access directly to my ebooks stored on my pc by using Zotero.
Greetings, Maria!