Summary of the zettelkasten note taking method from the creator, Niklas Luhmann, himself in the form of lecture notes.
Article is in German but a few choice, bot-translates quotes follow:
I. Statement of the problem
Linear accumulation of information that is meant to remain available.
Memory solves the problem of retrieval independently of the order of input, but it has limited capacity.
With written notes, the same problem reappears.
…
Try to formulate things in your own words. This makes a strict separation of one’s own and others’ ideas necessary. Critical summarizing is at the same time one’s own thinking work, at the same time a learning process, at the same time a honing of one’s own language.
Lecture notes, notes on conversations, ideas arising on all sorts of occasions can also be worked into the zettelkasten. Becoming outdated is unavoidable. Proof of learning success.
And perhaps most importantly:
In conclusion, from personal experience, others work differently.