diff --git a/trees/cb/cb-docs.factor b/trees/cb/cb-docs.factor
index ff6e702..91c8318 100644
--- a/trees/cb/cb-docs.factor
+++ b/trees/cb/cb-docs.factor
@@ -18,6 +18,8 @@ $nl
 "Crit-bit trees conform to the assoc protocol."
 ;
 
+ABOUT: "trees.cb"
+
 HELP: CB{
 { $syntax "CB{ { key value }... }" }
 { $values { "key" "a key" } { "value" "a value" } }
diff --git a/trees/cb/cb-tests.factor b/trees/cb/cb-tests.factor
index d1fc611..1576042 100644
--- a/trees/cb/cb-tests.factor
+++ b/trees/cb/cb-tests.factor
@@ -53,14 +53,14 @@ IN: trees.cb.tests
 
 ! Collision
 {
-    CB{ { B{ 110 } B{ 110 } } }
+    CB{ { B{ 110 } f } }
 } [
     CB{ { f f } }
-    B{ 110 } dup rot [ set-at ] keep
+    f B{ 110 } rot [ set-at ] keep
 ] unit-test
 
 ! Colliding trees are still not equal
 { f } [
     CB{ { f f } }
-    CB{ { B{ 110 } B{ 110 } } } =
+    CB{ { B{ 110 } f } } =
 ] unit-test
diff --git a/trees/cb/summary.txt b/trees/cb/summary.txt
index 1ba030c..827a94e 100644
--- a/trees/cb/summary.txt
+++ b/trees/cb/summary.txt
@@ -1,2 +1 @@
-Critical bit trees as described in http://cr.yp.to/critbit.html.
-They are implemented as subclasses of trees.
+Critical bit trees as described in http://cr.yp.to/critbit.html