diff --git a/01_1_opac_vs_discovery-system.md b/01_1_opac_vs_discovery-system.md
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-# OPAC vs. Discovery-System
+# 1.1 OPAC vs. Discovery-System
 
 ## Präsentation Gerald Steilen (2012)
 http://www.slideshare.net/steilen/discoverysysteme-die-opacs-der-zukunft