diff --git a/SUMMARY.md b/SUMMARY.md
index 175a656..c195f73 100644
--- a/SUMMARY.md
+++ b/SUMMARY.md
@@ -9,7 +9,6 @@
   * [Contract](core-principles/contract.md)
   * [Testing](core-principles/testing.md)
   * [Design Maturity](core-principles/design-maturity.md)
-  * [Implementation Maturity](core-principles/implementation-maturity.md)
   * [Robustness](core-principles/robustness.md)
   * [Minimal API Surface](core-principles/minimal-api-surface.md)
   * [Rules for Extending](core-principles/rules-for-extending.md)
diff --git a/core-principles/robustness.md b/core-principles/robustness.md
index 4c4efd0..afe94cd 100644
--- a/core-principles/robustness.md
+++ b/core-principles/robustness.md
@@ -5,5 +5,5 @@ Every API implementation and API consumer **MUST** follow Postel's law:
 >
 > _– [John Postel](https://en.wikipedia.org/wiki/Robustness_principle)_
 
-That is, send as little as possible and be tolerant as possible while consuming another service ([tolerant reader](https://martinfowler.com/bliki/TolerantReader.html)).
+That is, send the absolutely necessary minimum and be tolerant as possible while consuming another service ([tolerant reader](https://martinfowler.com/bliki/TolerantReader.html)).