diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 5777375..c695fc7 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -31,7 +31,7 @@ I'll be using
 
 but any CC license that doesn't include the NC or ND clauses should be fine.
 
-Please put a copyright and license statement either in your entry or add it
+Please put a copyright and license statement (an [SPDX tag](https://spdx.org/) would be fine) either in your entry or add it
 to the [LICENSE.md](LICENSE.md) file.
 
 I haven't given workflow or branching models a lot of thought for this just