Ending of period defined by weeks - Polish Civil Code

When a period defined by weeks shall end according to the provisions of the Polish Civil Code?

According to the article 112 of the Polish Civil Code a period defined by weeks, by monts or by years shall end on the expiration of the day which corresponds in name or date to the starting day of the period, and if there is no such day in the concluding month – on the last day of that month. However, where the age of the natural person is reckoned the period shall end with the beginning of the last day.

legal status as of: 04.01.2013