Description of the illustration flashback_query_clause.eps

{ VERSIONS BETWEEN { SCN | TIMESTAMP }
    { expr | MINVALUE } AND { expr | MAXVALUE }
| VERSIONS PERIOD FOR valid_time_column BETWEEN
    { expr | MINVALUE } AND { expr | MAXVALUE }
| AS OF { SCN | TIMESTAMP } expr
| AS OF PERIOD FOR valid_time_column expr
}