added '@' for context, rewriting query X:sa as #BEG(X , sa), updated examples
diff --git a/examples/cosmas2_18.json b/examples/cosmas2_18.json
new file mode 100644
index 0000000..944a465
--- /dev/null
+++ b/examples/cosmas2_18.json
@@ -0,0 +1,12 @@
+{
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "query" : {
+    "@type" : "korap:group",
+    "operation" : "operation:submatch",
+    "spanRef" : [ 0, 1 ],
+    "operands" : [ {
+      "@type" : "korap:span",
+      "key" : "s"
+    } ]
+  }
+}
\ No newline at end of file