diff --git a/src/Alexandrie-Cairo/AeCairoLinearGradientPattern.class.st b/src/Alexandrie-Cairo/AeCairoLinearGradientPattern.class.st
index 59b2c60..fa008ff 100644
--- a/src/Alexandrie-Cairo/AeCairoLinearGradientPattern.class.st
+++ b/src/Alexandrie-Cairo/AeCairoLinearGradientPattern.class.st
@@ -31,6 +31,7 @@ AeCairoLinearGradientPattern class >> from: aFromPoint to: aToPoint addStopsFrom
 
 { #category : #'private - ffi' }
 AeCairoLinearGradientPattern class >> unownedNewFromX: fromX fromY: fromY toX: toX toY: toY [
+	"See: https://www.cairographics.org/manual/cairo-cairo-pattern-t.html#cairo-pattern-create-linear"
 
 	^ self ffiCall: #(
 		AeCairoLinearGradientPattern
diff --git a/src/Alexandrie-Cairo/AeCairoSurfacePattern.class.st b/src/Alexandrie-Cairo/AeCairoSurfacePattern.class.st
index 670e60d..29588c9 100644
--- a/src/Alexandrie-Cairo/AeCairoSurfacePattern.class.st
+++ b/src/Alexandrie-Cairo/AeCairoSurfacePattern.class.st
@@ -19,6 +19,7 @@ AeCairoSurfacePattern class >> surface: aCairoSurface [
 
 { #category : #'private - ffi' }
 AeCairoSurfacePattern class >> unownedNewFor: aCairoSurface [
+	"See: https://www.cairographics.org/manual/cairo-cairo-pattern-t.html#cairo-pattern-create-for-surface"
 
 	^ self ffiCall: #(
 		AeCairoSurfacePattern