diff --git a/include/ldap.h b/include/ldap.h
index 665394817a7153decf9704e2a2145511e6cdb6a1..190bfc59441582e0894363d5d30d781b906b064f 100644
--- a/include/ldap.h
+++ b/include/ldap.h
@@ -366,7 +366,9 @@ typedef struct ldapcontrol {
 #define LDAP_CONTROL_VLVRESPONSE    "2.16.840.1.113730.3.4.10"
 
 /* Netscape Password policy response controls */
+/* https://docs.oracle.com/cd/E19957-01/816-5618-10/netscape/ldap/controls/LDAPPasswordExpiredControl.html */
 #define LDAP_CONTROL_X_PASSWORD_EXPIRED		"2.16.840.1.113730.3.4.4"
+/* https://docs.oracle.com/cd/E19957-01/816-5618-10/netscape/ldap/controls/LDAPPasswordExpiringControl.html */
 #define LDAP_CONTROL_X_PASSWORD_EXPIRING	"2.16.840.1.113730.3.4.5"
 
 /* LDAP Unsolicited Notifications */