diff --git a/src/com/characterforming/ribose/IToken.java b/src/com/characterforming/ribose/IToken.java
index 38da48a..34b115f 100644
--- a/src/com/characterforming/ribose/IToken.java
+++ b/src/com/characterforming/ribose/IToken.java
@@ -28,7 +28,8 @@
  * corresponding to backquoted Unicode text in effector parameters in ribose patterns.
  * To ribose a token may represent a literal or a symbolic reference to a transducer,
  * field or signal prefixed with a special byte designating the type of the referent
- * (@, ~ or !, respectively).
+ * (@, ~ or !, respectively). Literal tokens that require a type prefix, (eg {@code
+ * out[`!Aliteral`]}) can escape the prefix by doubling it ({@code `!!Aliteral`]}).
  * <br><br>
  * Arrays of {@code IToken} objects, corresponding to effector parameters, are conveyed
  * to proxy parameterized instances during effector parameter precompilation. See the