In the present paper the author
develops a new periodic algorithm for certain algebraic number fields and calculates
units in these fields from its periodicity. This algorithm (abbr. ACF) is a
modification of the Jacobi-Perron Algorithm, where for the first time the expanding
of the complex (not only real) numbers was possible. The ACF discloses new units of
which the already known ones are special cases, and it has the advantage that many
results in the theory of units can be derived by means of a unified periodic
algorithm.