diff --git a/journal/2021-02-20.md b/journal/2021-02-20.md
index 0da6fa10f..4d4696b2d 100644
--- a/journal/2021-02-20.md
+++ b/journal/2021-02-20.md
@@ -6,6 +6,7 @@
   - [[bolo bolo]]
   - [[the precipice]]
   - [[a pattern language]]
+  - [[the evolution of cooperation]]
   - [[scattered minds]]
 - [[rust]]
 - [[indras net]]