Luhmann's description of his zettelkasten system. As he describes it, it is essentially just a collection of numbered cards, which refer to one another by number and have no top-down organization.
I read Manfred Kuehn's translation, from which quotation are taken.
Luhmann notes the bootstrapping problem for this system:
The slip box needs a number of years in order to reach critical mass. Until then, it functions as a mere container from which we can retrieve what we put in.
Ahrens suggests that the value of the slip-box is that you can paste together a series of notes, do some light editing, and have a draft of a publication (Ahrens2017). Luhmann does not seem to agree:
Theoretical publications do therefore not result from simply copying what can already be found in the slip box.