Unit Definition (alen [Scandinavia])
The Alen is a traditional Scandinavian unit of distance, which is very similar to the North German Elle: which is roughly equal to 2 feet or 60 centimeters.

Unit Definition (bohr)
The Bohr is a unit of distance commonly used in particle physics. It was named after the Danish physicist Niels Bohr (1885-1962), who explained the structure of atoms in a famous paper in 1913. The Bohr radius represents the mean distance between the proton and the electron in an unexcited hydrogen atom. It equals about 52.918 picometers (pm), or 52.918 x 10e-12 meter.