diff --git a/content/notes/09-intro-to-c-2.md b/content/notes/09-intro-to-c-2.md
index 04e9d847f..5ceebe7c2 100644
--- a/content/notes/09-intro-to-c-2.md
+++ b/content/notes/09-intro-to-c-2.md
@@ -34,4 +34,14 @@ names are allocated to emmory locations of declaration
 - changes to the parameter do not propogate to the caller
 
 ## Call by address
-- address of parameter is passed to the rountine
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+- address of parameter is passed to the rountine
+- changes do propogate back to the caller
+- more efficient because we only need to pass a pointer and not a value
+
+### Multiple results
+- c routine can return at most one value
+- you can use input parameters which are pointers for "returning" results
+
+### Arrays
+- strings
+- 
\ No newline at end of file