The answer is active-recall.
The expository nature literature notes might impose it’s structure into the permanent notes. Since it is written in the perspective of the reference, the concept is tidy. However, Zettels don’t work if they aren’t written in relation to your specific knowledge management system.
Anki is probably the best tool for practicing active recall. Although the timing of this varies from card to card, I often find that after I learn a card, I get new insights as I recall them. Since these insights reflect my understanding of the concept, I find myself updating the flashcard. Sometimes I even seek out relevant cards and update them as I see fit.
Well I think this is a very powerful way to approach permanent notes. With anki, I don’t have to plan writing them and although in a way I have automated the whole process, it is still very organic. What I’m gonna do now is draw in questions from my literature notes and let active recall guide me into writing the permanent notes.
Let your Zettels be lean and full of life.