Mention Rosen's book and "eventual source"

notes.md

@@ -206,6 +206,8 @@ 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).
 
+Lawrence Rosen's book *Open Source Licensing: Software Freedom and Intellectual Property Law* uses the term "eventual source".
+
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