Specifies parameters by which returned result should be ordered. Parameter sort order can be specified by appending :asc for an ascending sort order or :desc for a descending one to the parameter name. Default sort order is ascending and can be omitted. Multiple parameters should be separated by a comma.
Result can be ordered by the following parameters: key, title, description, date, link, author, size, duration, expires_date, status and updated.
Default is date:asc.