diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 54362864..953c9016 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -47,11 +47,11 @@ Mail-in-a-Box needs more tests. If you're still looking for a way to help out, w
 
 ## Public domain
 
-This project is in the public domain. Copyright and related rights in the work worldwide are waived through the [CC0 1.0 Universal public domain dedication][cc0]. See the LICENSE file in this directory.
+This project is in the public domain. Copyright and related rights in the work worldwide are waived through the [CC0 1.0 Universal public domain dedication][CC0]. See the LICENSE file in this directory.
 
 All contributions to this project must be released under the same CC0 wavier. By submitting a pull request or patch, you are agreeing to comply with this waiver of copyright interest.
 
-[cc0]: http://creativecommons.org/publicdomain/zero/1.0/
+[CC0]: http://creativecommons.org/publicdomain/zero/1.0/
 
 ## Code of Conduct