diff --git a/docs/framework/text_output.rst b/docs/framework/text_output.rst
index ff87abc1..b7592900 100644
--- a/docs/framework/text_output.rst
+++ b/docs/framework/text_output.rst
@@ -33,6 +33,7 @@ Formatting the output
 ---------------------
 
 Grammar:
+^^^^^^^^
 
 .. productionlist::
     units-format-spec: fill-and-align[opt] sign[opt] width[opt] precision[opt] units-specs[opt]
@@ -41,5 +42,5 @@ Grammar:
                : units-specs literal-char
     literal-char: any character other than '{' or '}'
     conversion-spec: '%' modifier[opt] type
-    modifier: one of 'E', 'O'
+    modifier: 'A'
     type: one of 'n', 'q', 'Q', 't', '%'
diff --git a/src/include/units/format.h b/src/include/units/format.h
index 78b4f694..d551a508 100644
--- a/src/include/units/format.h
+++ b/src/include/units/format.h
@@ -41,8 +41,8 @@ namespace units {
     //      any character other than { or }
     // conversion-spec:
     //      % modifier[opt] type
-    // modifier: one of
-    //      E O
+    // modifier:
+    //      A
     // type: one of
     //      n q Q t %