"ref"=>"O 18","format"=>"squared_stone","material"=>"bluestone","operator"=>"dutch","architect"=>"Ministerie van Oorlog","collection"=>"yes","format:top"=>"flat","inscription"=>"O"
"architect"=>"Ministerie van Oorlog","collection"=>"yes","format"=>"squared_stone","format:top"=>"flat","inscription"=>"O","material"=>"bluestone","operator"=>"dutch","ref"=>"O 23"
"ref"=>"O 4","format"=>"squared_stone","material"=>"bluestone","operator"=>"dutch","architect"=>"Ministerie van Oorlog","collection"=>"yes","format:top"=>"flat","inscription"=>"O"