  As a consequence of their work, Bruce C. Berndt and Ronald J. Evans in 1977
and Larry Joel Goldstein and Michael Razar in 1976 obtained a formula for the
square of the class number of an imaginary quadratic number field in terms of
Dedekind sums. Here we focus only on this formula and give a new short and
simple proof of it. We finally express the relative class numbers of imaginary
abelian number fields in terms of Dedekind sums.
