1. N.R. Council, others, Connecting Quarks with the Cosmos: Eleven Science Questions for the New Century (National Academies Press, 2003)
2. N. Science, T. Council, A 21st Century Frontier for Discovery: The Physics of the Universe (2004)
3. G.V. Kulikov, G.B. Khristiansen, On the size spectrum of extensive air showers. Sov. Phys. Jetp. 35, 441 (1959)
4. W.D. Apel, J.C. Arteaga, A.F. Badea et al., Energy spectra of elemental groups of cosmic rays: update on the KASCADE unfolding analysis. Astropart. Phys. 31, 86 (2009). https://doi.org/10.1016/j.astropartphys.2008.11.008
5. J. Linsley, Primary cosmic rays of energy 10$$^{17}$$ to $$10^{20}$$ eV, the energy spectrum and arrival directions. in ICRC, Vol. 4 (1963) p. 77