From 8cc40f152c49a8fe039e78bb6355fb077b932117 Mon Sep 17 00:00:00 2001
From: tim30b <tim.toenz@ost.ch>
Date: Fri, 30 Jul 2021 10:57:58 +0200
Subject: add crystal video source

---
 buch/papers/punktgruppen/references.bib | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/buch/papers/punktgruppen/references.bib b/buch/papers/punktgruppen/references.bib
index a29640c..b669036 100644
--- a/buch/papers/punktgruppen/references.bib
+++ b/buch/papers/punktgruppen/references.bib
@@ -42,3 +42,12 @@
   url = {http://archive.today/2021.07.22-083802/http://xrayweb.chem.ou.edu/notes/symmetry.html},
   urldate = {2021-07-22},
 }
+
+@online{punktgruppen:restriction,
+  title = {Structure of Materials},
+  author = {Silvija Gradecak-Garaj},
+  year = {2020},
+  month = {4},
+  day = {9},
+  url = {https://www.youtube.com/watch?v=Ia2eHF1ZKoI},
+  urldate = {2021-07-30},
\ No newline at end of file
-- 
cgit v1.2.1