anchor.diff:    UPCOMING
   }
   
  +enum ExhibitionPeriodFormat {
  +  # Long formatted period e.g. February 25 – May 24, 2015
  +  LONG
  +
  +  # Short formatted period e.g. Feb 25 - May 24, 2015
  +  SHORT
  +}
  +
   type External {
     auctionHouses(size: Int, term: String): [ExternalAuctionHouse!]!
     fairs(size: Int, term: String): [ExternalFair!]!
  
positive.code:   eventType: String
  
    # A formatted description of the start to end dates
    exhibitionPeriod: String
  
    # A formatted description of the start to end dates with abbreviated months
    shortExhibitionPeriod: String
    startAt(
      format: String
  
  
negative.code:   ): String
  
    # A formatted description of the start to end dates
    exhibitionPeriod(
      # Formatting option to apply to exhibition period
      format: ExhibitionPeriodFormat
    ): String
  
    # The exhibitors with booths in this fair with letter.
    exhibitorsGroupedByName: [FairExhibitorsGroup]
  