The Bose-Einstein correlations (BEG) observed in hadronic experiments
are reviewed. Emphasis is given to the factors that can modify the BEC
parameters. The experimental results are studied and the behavior of
the parameters is examined. The available data and the currently used
parametrizations seem to indicate that the radius of particle sources
does not depend on the energy of the system. However, new types of par
ametrization have been introduced and applied in certain experiments,
which show a different behavior. In these cases, the data are not conc
lusive about the type of parametrization and the parameter values.