anchor.diff:  		(:type :url,(s-prefix "schema:additionalType"))
   		(:start-date :date ,(s-prefix "schema:startDate"))
   		(:end-date :date ,(s-prefix "schema:endDate"))
  -		(:created :date ,(s-prefix "dcterms:created"))
  -		(:modified :date ,(s-prefix "dcterms:modified")))
  +		(:created :datetime ,(s-prefix "dcterms:created"))
  +		(:modified :datetime ,(s-prefix "dcterms:modified")))
     :resource-base (s-url "http://data.bravoer.be/id/events/")
     :has-many `((musician :via ,(s-prefix "bravoer:attendee")
   			:as "attendees")
  
positive.code: 		(:organization-name :string ,(s-prefix "vcard:hasOrganizationName"))
                  (:communication :string ,(s-prefix "bravoer:communicationsMedium"))
  		(:email :url ,(s-prefix "vcard:hasEmail"))
  		(:created :date ,(s-prefix "dcterms:created"))
  		(:modified :date ,(s-prefix "dcterms:modified")))
    :resource-base (s-url "http://data.bravoer.be/id/contacts/")
    :has-one `((address :via ,(s-prefix "locn:address")
  		      :as "address"))
  
negative.code: (define-resource sponsorship ()
    :class (s-prefix "bravoer:Sponsorship")
    :properties `((:amount :double ,(s-prefix "schema:amount"))
  		(:created :datetime ,(s-prefix "dcterms:created"))
  		(:modified :datetime ,(s-prefix "dcterms:modified")))
    :resource-base (s-url "http://data.bravoer.be/id/sponsorships/")
    :has-one `((event :via ,(s-prefix "bravoer:sponsored")
  		     :as "event")
  