Hey.
I just added a external link to Calibre from inside a literature note.
This is how that looks.
[The 1-Page Marketing Plan](<calibre://search/_?q=The 1-Page Marketing Plan>)
When you click the link it searches for the query (denoted with ?q=) in your current library (Replace the underscore with your preferred library. Leave it to search the currently selected one).
Easy when you want to pull up a book real quickly.
Calibre version 5.5 and higher required.
EDIT: You can also pull up the exact book via its book-id. Searching is faster, for me.
https://manual.calibre-ebook.com/url_scheme.html