diff --git a/basis/xml/data/data-docs.factor b/basis/xml/data/data-docs.factor
index 97aa362c17..17a63348e3 100644
--- a/basis/xml/data/data-docs.factor
+++ b/basis/xml/data/data-docs.factor
@@ -201,7 +201,7 @@ HELP: notation-decl
 { $class-description "Describes the class of element declarations, like " { $snippet "<!NOTATION jpg SYSTEM './jpgviewer'>" } "." } ;
 
 HELP: <notation-decl>
-{ $values { "name" string } { "id" id } { "notation-decl" notation-decl } }
+{ $values { "name" string } { "id" string } { "notation-decl" notation-decl } }
 { $description "Creates an notation declaration object, of the class " { $link notation-decl } "." } ;
 
 HELP: doctype-decl
diff --git a/basis/xml/data/data.factor b/basis/xml/data/data.factor
index 9752d19bf2..3a9db764ff 100644
--- a/basis/xml/data/data.factor
+++ b/basis/xml/data/data.factor
@@ -110,6 +110,8 @@ C: <system-id> system-id
 TUPLE: public-id { pubid-literal string } { system-literal string } ;
 C: <public-id> public-id
 
+UNION: id system-id public-id ;
+
 TUPLE: dtd
     { directives sequence }
     { entities assoc }
@@ -118,7 +120,7 @@ C: <dtd> dtd
 
 TUPLE: doctype-decl < directive
     { name string }
-    { external-id maybe{ system-id public-id } }
+    { external-id maybe{ id } }
     { internal-subset maybe{ dtd } } ;
 C: <doctype-decl> doctype-decl