  Bose-Einstein correlations in pairs of identical particles were analyzed in
e+ e- multihadron annihilations at ~91.2 GeV at LEP. The first studies involved
identical charged pions and the emitting source size was determined. Then the
study of charged kaons suggested that the radius depends on the mass of the
emitted particles. Subsequenty the dependence of the source radius on the event
multiplicity was analyzed. The study of the correlations in neutral pions and
neutral kaons extended these concepts to neutral particles. The shape of the
source was analyzed in 3 dimensions and was found not to be spherically
symmetric. In recent studies at LEP the correlations were analyzed in intervals
of the average pair transverse momentum and of the pair rapidity to study the
correlations between the pion production points and their momenta
(position-momentum correlations). The latest e+ e- data are consistent with an
expanding source.
