  We present an analytical formula for the Bose-Einstein correlations (BEC)
which includes effects of both Coulomb and strong final stateinteractions
(FSI). It was obtained by using Coulomb wave function together with the
scattering partial wave amplitude of the strong interactions describing data on
the $s$-wave phase shift. We have proved numerically that this method is
equivalent to solving Schr\"{o}dinger equation with Coulomb and the $s$-wave
strong interaction potentials. As an application we have analysed, using our
formula which includes the degree of coherence and the long range correlation,
the data for $e^+e^-$ annihilations. We have found that the degree of coherence
present in our formula approaches approximately unity whereas the long range
correlation parameter becomes approximately zero. These results suggest that
the physical meanings of the fractional degree of coherence and the long range
correlation observed in various other analyses can most probably be attributed
to FSI.
