diff --git a/README.md b/README.md
index 6135633..e0e8e27 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@
 This is an experimental gem that extracts low-level PDF functionality from
 Prawn. More details to come soon!
 
-## Refernce materials
+## Reference materials
 
 * [PDF 1.7 Reference][1] ([Archived][2])
 * [Errata to PDF 1.7][3] ([Archived][4])