DATE PERIOD

A DATE_PERIOD refers to an event that occurred over a period of time and is different to a DATE_RANGE.

DATE_PERIOD:= {Size=7:35}
[
 FROM <DATE> |
 TO <DATE> |
 FROM <DATE> TO <DATE>
]

Examples

FROM 1904 TO 1915

= The state of some attribute existed from 1904 to 1915 inclusive.

FROM 1904

= The state of the attribute began in 1904 but the end date is unknown.

TO 1915

= The state ended in 1915 but the begin date is unknown.