Macrame Collective has a lovely post about Margaretenspitze a macrame technique created by Margarete Naumann in the early 1900s. Of late I've seen many examples of this intricate knot work on the Micro-macrame Facebook page and have become intrigued. Here's a lovely piece by Adriana Lazzari
Tombolo Disegni and it is in Italian, so brush up on your language skills!
There's another book available on Margaretenspitze by Lotte Heinemann. This one is in German.
It can be ordered by contacting the Margaretenspitze website.