Mention 2018 CC report on "springing licenses"

notes.md

@@ -202,6 +202,10 @@ suggesting some of these cases (which can be fairly famous, like Netscape
 Navigator!), but I think these should be thought of as more of a one-time
 "change" than a "delay".
 
+See also [Creative Commons Final Report: On the Viability and
+Development of Springing
+Licenses](https://creativecommons.org/wp-content/uploads/2018/07/Springing-licenses-FINAL.pdf).
+
 # Threads where we have posted
 
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