date.txt (date period)
contains one data record for each week for which the timetable data are available.
Fields :
1 char calendar week, e.g. 36
2 char day and month of the Monday in this week, e.g. 4.9.
3 date full date of the month in the form YYYYMMDD e.g. 20080904
4 char school week, e.g. 1
Example :
36 4.9. 20080904 1