diff --git a/source/part-1-workspace/maintainable-applications/_index.adoc b/source/part-1-workspace/maintainable-applications/_index.adoc
index 77bf81d..cb98325 100644
--- a/source/part-1-workspace/maintainable-applications/_index.adoc
+++ b/source/part-1-workspace/maintainable-applications/_index.adoc
@@ -13,6 +13,14 @@ include::12-factors.adoc[]
 include::maintainable-applications.adoc[]
 include::mccabe.adoc[]
 
-=== robustes et flexibles
+=== robustes, flexibles, ...
 
 include::solid.adoc[]
+
+=== et testées.
+
+[quote]
+----
+Tests are part of the system.
+-- Robert C. Martin, Clean Architecture, page 250, Chapitre 28 - The Boundaries
+----
\ No newline at end of file