diff --git a/etc/vocabs_additional.yaml b/etc/vocabs_additional.yaml
index 7ace17bc..24137e1a 100644
--- a/etc/vocabs_additional.yaml
+++ b/etc/vocabs_additional.yaml
@@ -15,6 +15,10 @@ c4o:
   uri: "http://purl.org/spar/c4o/"
   source: "http://www.sparontologies.net/ontologies/c4o/source.ttl"
 
+cert:
+  uri: "https://www.w3.org/ns/auth/cert#"
+  source: "http://www.w3.org/ns/auth/cert.n3"
+
 co:
   uri: "http://purl.org/co/"
   source: "var/vocabs/collections.owl"
diff --git a/lib/vocabs/cert.rb b/lib/vocabs/cert.rb
new file mode 100644
index 00000000..8ffeab22
--- /dev/null
+++ b/lib/vocabs/cert.rb
@@ -0,0 +1,12 @@
+# -*- encoding: utf-8 -*-
+# frozen_string_literal: true
+# This file generated automatically using rdf vocabulary format from https://www.w3.org/ns/auth/cert#
+require 'rdf'
+module RDF::Vocab
+  # @!parse
+  #   # Vocabulary for <https://www.w3.org/ns/auth/cert#>
+  #   class CERT < RDF::StrictVocabulary
+  #   end
+  class CERT < RDF::StrictVocabulary("https://www.w3.org/ns/auth/cert#")
+  end
+end
diff --git a/nanoc.yaml b/nanoc.yaml
index 67f6fbe8..066d4b77 100644
--- a/nanoc.yaml
+++ b/nanoc.yaml
@@ -56,7 +56,7 @@ data_sources:
       instances:  [ dbo, dbr, yago ]
       technical:  [ deps, doap, vann, voaf, void ]
       pentandra:  [ pentandra, pentandra-blog, pentandra-website ]
-      extra:      [ essglobal-activities, essglobal-legalform, essglobal-qualifiers, essglobal-typeoflabour, sioct, xsd ]
+      extra:      [ cert, essglobal-activities, essglobal-legalform, essglobal-qualifiers, essglobal-typeoflabour, sioct, xsd ]
 
   - type: company
     company_metafile: 'var/company.yaml'