doc update
diff --git a/docs/x509.rst b/docs/x509.rst
index 7eb47a3..751e077 100644
--- a/docs/x509.rst
+++ b/docs/x509.rst
@@ -488,7 +488,7 @@
 .. data:: OID_BASIC_CONSTRAINTS
 
     Corresponds to the dotted string ``"2.5.29.19"``. The identifier for the
-    basic constraints extension.
+    :class:`BasicConstraints` extension type.
 
 
 Exceptions