WeekDA is a DA (Desk Accessory) to input the week number, the weekly number follows ISO-8601. Format
The format of the week number is "Year + 'w' + Week number". For example, January 1, 2004 is converted to "04w01".
The start day of the week (Sunday or Monday) follows the system preferences. Here are some key features of "WeekDA":

• The week number means a number in which specific date is week of the year.
• It can be used in the editable field.
• When starting with no text selected, the dialog to select the date is displayed, and the week number of the date selected there is inserted into the cursor position.
• When starting after the text that shows the date is selected, the date is replaced with the week number.