Update oaf.md

projects/oaf.md

@@ -31,7 +31,7 @@ OAF was a DFG-funded research project running from 2014-2020 and headed by Micha
 and Florian Rabe originally at Jacobs University Bremen and later at FAU Erlangen-Nürnberg.
 It centered on the integration of formal mathematical libraries.
 
-Both the [original proposal](http://kwarc.info/kohlhase/projects/oaf.pdf) and the [final report](projects/oaf-report.pdf) are available.
+Both the [original proposal](http://kwarc.info/kohlhase/projects/oaf.pdf) and the [final report](../oaf-report.pdf) are available.
 
 Formal/symbolic systems and their libraries are non-interoperable because they are based
 on differing, mutually incompatible foundations (e.g., set theory, higher-order logic,