diff --git a/chapter7/README.md b/chapter7/README.md
index 84d0f79..64ed2c1 100644
--- a/chapter7/README.md
+++ b/chapter7/README.md
@@ -1,5 +1,8 @@
-# DFS BFS on rooted tree
+# BFS DFS on rooted tree (connected acyclic graph)
 
 The BFS example uses a queue which results in a breadth first search. When a directory is found its contents are appended to the queue to be processed later
 
 The DFS example uses the call stack which results in a depth first search. When a directory is found it is recursively passed to files_with_extension to be processed immediately.
+
+Note. DFS cannot be used to find the shortest path. In the mango seller example, a DFS search may have found a second or third degree
+seller before a first. However, DFS may be used to find the topological sort.