Convert from bunder to dunum, dunham

Unit Definition (bunder)
The Bunder is a traditional Dutch unit of land area. Since the adoption of the metric system in the Netherlands in 1809 the bunder has been considered equal to the hectare (2.471 acres). Historically, the unit varied with locality, generally in the range 0.85-1.3 hectare. The unit was also used in Belgium, being called the bonnier in French-speaking provinces.

Unit Definition (dunum, dunham)
The Dunum is a traditional unit of land area in the Middle East and the Balkans. The unit is of Turkish origin, but it seems to be obsolete in modern Turkey. As it is commonly used today in Israel and Palestine and in Croatia and other areas of the former Yugoslavia, the dunum is a metric unit equal to 1000 square meters or 0.1 hectare (about 0.2471 acre). The traditional size seems to have been around 900 square meters. In Mesopotamia and Arabia, the dunum was a larger unit, traditionally in the range of 2500 to 4000 square meters. In modern Iraq, the dunum is now standardized at 2500 square meters (about 0.6179 acre).