1. E. Recami: Rivista Nuovo Cira. 9 (1986), issue no. 6, pp. 1–178.
2. P.O.Fröman: Arch. Hist. Exact Sci. 48 (1994) 373–380.
3. R. Mignani and E. Recami: Rivista Nuovo Cim. 4 (1974) 209–290; E398.
4. E. Recami: in Albert Einstein 1879–1979: Relativity, Quanta and Cosmology, ed. by F. De Finis and M.Pantaleo, vol. 2 (Johnson Reprint Co.; New York, 1979), p. 537–597. This book exists also in Italian and in Russian.
5. P. Caldirola & E. Recami: in Italian Studies in the Philosophy of Science,ed. by M.L.Dalla Chiara (Reidel: Boston, 1980), p.249–298.