Convert from jerib to tunnland

Unit Definition (jerib)
The jerib is a traditional unit of land area in the Middle East and southwestern Asia. The jerib originally varied considerably from one area to another. In modern times it has become identified with the hectare in many countries, including Turkey and Iran. In Afghanistan, however, it is usually equal to 1/5 hectare (2000 square meters or 0.494 acre).

Unit Definition (tunnland)
The tunnland is a traditional unit of land area in Sweden. The tunnland is equal to 56 000 square Stockholm feet (kvadratfot); this is equivalent to 4936.4 square meters, 0.493 64 hectare, or about 1.220 English acre. The tunnland was divided into 32 kappland. Like the Danish tønde land (see above), this unit originated as the area that could be planted with one tunn (barrel) of seed.