diff --git a/README.md b/README.md
index 0bf76cd..90126e7 100644
--- a/README.md
+++ b/README.md
@@ -52,7 +52,7 @@ of search-based optimization for exploring models
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-9. <a href="src/PSO.md">PSO</a><br>
+9. <a href="PSO.md">PSO</a><br>
 8. <a href="src/gadgets.md">Gadgets</a><br>
 7. <a href="DE.md">DE</a><br>
 6. <a href="src/doc/Hoa-NCSU-2015.pdf">Effort Estimation<br> (Dr. Hoa's talk)</a><br>