  Multiple solutions exist in various experimental situations whenever the sum
of several amplitudes is used to fit the experimentally measured distributions,
such as the cross section, the mass spectrum, or the angular distribution. We
show a few examples where multiple solutions were found, while only one
solution was reported in the publications. Since there is no existing rules
found in choosing any one of these solutions as the physics one, we propose a
simple rule which agrees with what have been adopted in previous literatures:
the solution corresponding to the minimal magnitudes of the amplitudes must be
the physical solution. We suggest test this rule in the future experiments.
