On the Extensive Air Shower density spectrum
  In search for new methods of determining the primary energy spectrum of Cosmic Rays, the attention was paid to the density spectrum measurement. New methods available at present warrant an accurateness of conclusions derived from the density spectrum measurements. The general statement about the change of the spectral index of the charged particle density spectrum is confirmed very clearly. Results concerning the shower size and primary energy spectra are also presented and discussed. Interesting future prospects for applications of the density spectrum method are proposed. 
Aleksander Zawadzki (College de France), Tadeusz Wibig (Univ. of   Lodz), Jerzy Gawin (Institute of Nuclear Studies, Lodz)