An extended universality of electron distributions in cosmic ray showers   of high energies and its application
  It is shown that the shape of any electron distribution in a high energy air shower is the same in all such showers, if taken at the same age, independently of the primary energy, mass and thus, of the interaction model. 
Maria Giller, Andrzej Smialkowski and Grzegorz Wieczorek
astro-ph.HE hep-ex