diff --git a/library/error/src/visitor/file_output_error_visitor.e b/library/error/src/visitor/file_output_error_visitor.e
index 588c4250..49e9493f 100644
--- a/library/error/src/visitor/file_output_error_visitor.e
+++ b/library/error/src/visitor/file_output_error_visitor.e
@@ -31,7 +31,7 @@ feature -- Access
 
 feature -- Output
 
-	output_string (a_str: detachable STRING_GENERAL)
+	output_string (a_str: detachable READABLE_STRING_GENERAL)
 			-- Output Unicode string
 		do
 			if a_str /= Void then
@@ -50,4 +50,14 @@ feature -- Output
 			file.put_new_line
 		end
 
+note
+	copyright: "2011-2012, Eiffel Software and others"
+	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
+	source: "[
+			Eiffel Software
+			5949 Hollister Ave., Goleta, CA 93117 USA
+			Telephone 805-685-1006, Fax 805-685-6869
+			Website http://www.eiffel.com
+			Customer support http://support.eiffel.com
+		]"
 end
diff --git a/library/error/src/visitor/output_error_visitor.e b/library/error/src/visitor/output_error_visitor.e
index 22d1128d..50b05b3d 100644
--- a/library/error/src/visitor/output_error_visitor.e
+++ b/library/error/src/visitor/output_error_visitor.e
@@ -13,7 +13,7 @@ inherit
 
 feature -- Output
 
-	output_string (a_str: detachable STRING_GENERAL)
+	output_string (a_str: detachable READABLE_STRING_GENERAL)
 			-- Output Unicode string
 		deferred
 		end
@@ -21,7 +21,7 @@ feature -- Output
 	output_any (obj: detachable ANY)
 			-- Output Unicode string
 		do
-			if attached {STRING_GENERAL} obj as l_str then
+			if attached {READABLE_STRING_GENERAL} obj as l_str then
 				to_implement ("Convert into UTF-8 or console encoding before output")
 				output_string (l_str)
 			elseif obj /= Void then
diff --git a/library/error/src/visitor/text_output_error_visitor.e b/library/error/src/visitor/text_output_error_visitor.e
index bff7f86f..b79b1b75 100644
--- a/library/error/src/visitor/text_output_error_visitor.e
+++ b/library/error/src/visitor/text_output_error_visitor.e
@@ -31,7 +31,7 @@ feature -- Access
 
 feature -- Output
 
-	output_string (a_str: detachable STRING_GENERAL)
+	output_string (a_str: detachable READABLE_STRING_GENERAL)
 			-- Output Unicode string
 		do
 			if a_str /= Void then
@@ -50,4 +50,14 @@ feature -- Output
 			buffer.append_character ('%N')
 		end
 
+note
+	copyright: "2011-2012, Eiffel Software and others"
+	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
+	source: "[
+			Eiffel Software
+			5949 Hollister Ave., Goleta, CA 93117 USA
+			Telephone 805-685-1006, Fax 805-685-6869
+			Website http://www.eiffel.com
+			Customer support http://support.eiffel.com
+		]"
 end