diff --git a/build.xml b/build.xml
index 426d0610..e2058b5b 100644
--- a/build.xml
+++ b/build.xml
@@ -11,6 +11,8 @@
       <src path="src"/>
       <src path="tests"/>
       <classpath path="lib/junit-4.8.2.jar"/>
+      <classpath path="lib/slf4j-api-1.6.1.jar"/>
+      <classpath path="lib/slf4j-simple-1.6.1.jar"/>
     </javac>
   </target>
 
@@ -43,4 +45,4 @@
     <delete dir="dist"/>
     <delete dir="docs"/>
   </target>
-</project>
\ No newline at end of file
+</project>