diff --git a/src/main/cljc/org/domaindrivenarchitecture/activity_pub_poc/owl.cljc b/src/main/cljc/org/domaindrivenarchitecture/activity_pub_poc/owl.cljc
index e473146..a78c43d 100644
--- a/src/main/cljc/org/domaindrivenarchitecture/activity_pub_poc/owl.cljc
+++ b/src/main/cljc/org/domaindrivenarchitecture/activity_pub_poc/owl.cljc
@@ -3,11 +3,20 @@
      is realized in deep implemented."""
   (:require [clojure.spec.alpha :as s]))
 
+; Properties:https://www.w3.org/TR/owl-ref/#Property
+; * Datatype properties link individuals to data values.
+; * Object properties link individuals to data values.
+
 ;http://www.w3.org/2002/07/owl#DatatypeProperty
 (s/def ::DatatypeProperty any?)
 
+;http://www.w3.org/2002/07/owl#ObjectProperty
+(s/def ::ObjectProperty any?)
+
 ;http://www.w3.org/2002/07/owl#FunctionalProperty
+;https://www.w3.org/TR/owl-ref/#FunctionalProperty-def
 (s/def ::FunctionalProperty any?)
 
 ;http://www.w3.org/2002/07/owl#DeprecatedProperty
+;https://www.w3.org/TR/owl-ref/#Deprecation
 (s/def ::DeprecatedProperty any?)