BRIEF [O.A.] Porro, Francesco Author: Porro, Francesco Recipient: Haeckel, Ernst Corporation: Observatorio Meterologico della R. Universita Dating: 06.05.1904
BRIEF [O.A.] Morselli, Enrico Author: Morselli, Enrico Recipient: Haeckel, Ernst Corporation: Clinica Psychiatrica Dating: 19.01.1896
BRIEF [O.A.] Morselli, Enrico Author: Morselli, Enrico Recipient: Haeckel, Ernst Corporation: Clinica Psychiatrica Dating: 10.03.1896