Because Evergreen notes should be concept-oriented reference-specific notes should be both brief and clearly separated from the note archive. They primarily exist to help you write durable notes.
Literature notes are typically a lightweight synthesis of observations collected while reading (see How to collect observations while reading). We can keep a quick summary of the work and those observations around for later literature lookup, but the bulk of the value will already have been absorbed into our lasting notes (see How to process reading annotations into evergreen notes). The reference-specific notes are mostly useful for their links into those lasting notes (Are literature notes necessary if we have automatic universal backlinks?).
There’s an important philosophical reason why we should keep these literature notes separate from our durable notes. The archive of lasting notes is the place where you Do your own thinking: you’ve interpreted others’ ideas into your own structure of knowledge. Direct quotes are fairly rare; durable notes are intentionally expressed in your own words. By contrast, literature notes are often mostly the author’s thoughts. They tend to lean on direct quotes, and even when our interpretation is offered, it’s in the context of the author’s ontology and claim system. It’s hard to hear yourself think, so we should clearly separate the space where we do our own thinking from these more direct representations of others’ thoughts.
Ahrens, Sönke. How to Take Smart Notes: One Simple Technique to Boost Writing, Learning and Thinking – for Students, Academics and Nonfiction Book Writers, 2017.
You need to take some form of literature note that captures your understanding of the text, so you have something in front of your eyes while you are making the slip-box note. But don’t turn it into a project in itself. Literature notes are short and meant to help with writing slip-box notes. Everything else either helps to get to this point or is a distraction.
Fleeting literature notes can make sense if you need an extra step to understand or grasp an idea, but they will not help you in the later stages of the writing process, as no underlined sentence will ever present itself when you need it in the development of an argument.
Luhmann, N. (1992). Communicating with Slip Boxes. In A. Kieserling (Ed.), & M. Kuehn (Trans.), Universität als Milieu: Kleine Schriften (pp. 53–61). Retrieved from http://luhmann.surge.sh/communicating-with-slip-boxes
I always have a slip of paper at hand, on which I note down the ideas of certain pages. On the backside I write down the bibliographic details. After finishing the book I go through my notes and think how these notes might be relevant for already written notes in the slip-box. It means that I always read with an eye towards possible connections in the slip-box.