diff --git a/src/net/jimmc/util/AbledPublisher.scala b/src/net/jimmc/util/AbledPublisher.scala
index e44bcf9..7ace32e 100644
--- a/src/net/jimmc/util/AbledPublisher.scala
+++ b/src/net/jimmc/util/AbledPublisher.scala
@@ -1,12 +1,12 @@
 package net.jimmc.util
 
-//For subscrobers of things that turn on and off
+//For subscribers of things that turn on and off
 class AbledPublisher extends Publisher[AbledPublisher.Abled]
 
 // use "import AbledPublisher._" to pick up these definitions
 object AbledPublisher {
 
-    abstract class Abled { val state:Boolean }
+    sealed abstract class Abled { val state:Boolean }
     case object Enabled extends Abled { override val state = true }
     case object Disabled extends Abled { override val state = false }
 
diff --git a/src/net/jimmc/util/Publisher.scala b/src/net/jimmc/util/Publisher.scala
index ae588e9..64ed99a 100644
--- a/src/net/jimmc/util/Publisher.scala
+++ b/src/net/jimmc/util/Publisher.scala
@@ -3,7 +3,7 @@ package net.jimmc.util
 /** Manage a subscriber list.
  * There are no guarantees on the order of subscribers in the list.
  * This code is a slightly modified version of ListenerManager
- * as published to my blog in 2008.
+ * as published to my blog in April 2009.
  */
 trait Publisher[E] {
     type S = (E) => Unit