diff --git a/timeline/week18.txt b/timeline/week18.txt
index 2188172071fbc4d32b913acea612b3fb1e3fccf4..180daf6bcc8ccce7cda35538a9a694ef0e135031 100644
--- a/timeline/week18.txt
+++ b/timeline/week18.txt
@@ -39,7 +39,7 @@ Week 18 (27.04.-03.05.)
 
 		-> the IRIs in the Isabelle exports have the following
 		   characters which are (according to automated tool
-		   `iriok' [4]) not valid: '|', '\' and ' '
+		   `iriok' [4]) not valid: '|', '\', ' ', '^'
 
 		-> importing the files w/ fixed IRIs I get new errors
                    from graphDB (sigh)
diff --git a/ulo/isabelle-prepare.sh b/ulo/isabelle-prepare.sh
index 94591094011382737d6c2886bd0b3f8c6c78c6b8..b1e787cee195ae604f9df22e6f1fcd25b9bc5ec2 100755
--- a/ulo/isabelle-prepare.sh
+++ b/ulo/isabelle-prepare.sh
@@ -26,5 +26,8 @@ for file in $files; do
     # uncompress, fix iris, compress again
     unxz "$file"
     sed -i 's/|/%7C/g' "$rdf_file"
+    sed -i 's/\\/%5C/g' "$rdf_file"
+    sed -i 's/ /%20/g' "$rdf_file"
+    sed -i 's/\^/%5E/g' "$rdf_file"
     gzip "$rdf_file"
 done