  The DELPHI and ALEPH experiments have released new results of the Fermi-Dirac
correlations for pp (\bar{p} \bar{p}) and Bose-Einstein correlations for K^0_s
K^0_s. Both experiments measure very small source radius for protons R \sim 0.1
fm. The source dimension for K^0_s K^0_s is in agreement with the previous
measurements for K^+ K^-, K^0_s K^0_s. These results, together with earlier LEP
measurements, establish the dependence of the correlation radius on the hadron
mass. This paper discusses some of the attempts to describe this phenomenon.
