Clusters in Very High Energy Cosmic Rays
  Arrival directions of cosmic rays with the energy E>4.10^{19} eV are analyzed by using data of the Yakutsk and AGASA (Japan) extensive air showers (EAS) arrays. It is supposed that the clusters can be formed as a result of decay of superheavy particles. The consequences of this supposition compare with experimental data. 
A.A. Mikhailov