diff --git a/main_opt.pdf b/main_opt.pdf
new file mode 100644
index 0000000..d310a64
Binary files /dev/null and b/main_opt.pdf differ
diff --git a/quellen.bib b/quellen.bib
index f420f3f..7daf4a9 100644
--- a/quellen.bib
+++ b/quellen.bib
@@ -105,7 +105,7 @@
 @image{imgsrc:prusik,
   author   = {Parkis},
   year     = {2008},
-  title    = {Prusíkův uzel (prusik knot)},
+  title    = {\textsf{Prusíkův uzel} (prusik knot)},
   url      = {https://commons.wikimedia.org/wiki/File:Prus%C3%ADk%C5%AFv_uzel.jpg},
   keywords = {image},
   note     = {Verföffentlicht unter der Lizenz: \glqq{}Creative Commons Attribution-Share Alike 3.0 Unported\grqq{}}