diff --git a/draft-ymbk-lsvr-l3dl-signing.xml b/draft-ymbk-lsvr-l3dl-signing.xml
index 34e482e..d88a782 100644
--- a/draft-ymbk-lsvr-l3dl-signing.xml
+++ b/draft-ymbk-lsvr-l3dl-signing.xml
@@ -281,12 +281,12 @@
   <section anchor="pki" title="Public Key Infrastructure Method">
       
     <t>
-      Using a PKI is almost the same as using TOFU, but with one
-      additional step: during verification of an OPEN PDU, after
-      extracting the Key field from the PDU but before attempting to
-      use it to verify the PDU's signature, the receiver MUST verify
-      the received key against the PKI to confirm that it's an
-      authorized key.
+      Using a PKI, <xref target="RFC5280"/>, is almost the same as using
+      TOFU, but with one additional step: during verification of an OPEN
+      PDU, after extracting the Key field from the PDU but before
+      attempting to use it to verify the PDU's signature, the receiver
+      MUST verify the received key against the PKI to confirm that it's
+      an authorized key.
     </t>
 
     <t>