  The representation of scalar products of Bethe wave functions in terms of the
Dual Fields, proven by A.G.Izergin and V.E.Korepin in 1987, plays an important
role in the theory of completely integrable models. The proof in
\cite{Izergin87} and \cite{Korepin87} is based on the explicit expression for
the "senior" coefficient which was guessed in \cite{Izergin87} and then proven
to satisfy some recurrent relations, which determine it unambiguously. In this
paper we present an alternative proof based on the direct computation.
