BRIEF [O.A.] Lionio, G... V... Author: Lionio, G... V... Recipient: Haeckel, Ernst Corporation: R. Universitá di Bologna
BRIEF [O.A.] Morandotti, Amadeo Author: Morandotti, Amadeo Recipient: Haeckel, Ernst Corporation: Redazione "La Patria il Resto del Carlino" Dating: 01.02.1907
BRIEF [O.A.] Siciliani, Pietro Author: Siciliani, Pietro Recipient: Haeckel, Ernst Dating: 07.02.1877
BRIEF [O.A.] Siciliani, Pietro Author: Siciliani, Pietro Recipient: Haeckel, Ernst Dating: 20.11.1876
BRIEF [O.A.] Siciliani, Pietro Author: Siciliani, Pietro Recipient: Haeckel, Ernst Dating: 18.02.1877
BRIEF [O.A.] Ercolani, G... B... Author: Ercolani, G... B... Recipient: Haeckel, Ernst Dating: 18.02.1877
BRIEF [O.A.] Ercolani, G... B... Author: Ercolani, G... B... Recipient: Haeckel, Ernst Dating: 24.03.1880
BRIEF [O.A.] Carati, Ernesto Author: Carati, Ernesto Recipient: Haeckel, Ernst Corporation: R. Università di Bologna Dating: 19.01.1909
BRIEF [O.A.] Foresti, Lodovico Author: Foresti, Lodovico Recipient: Haeckel, Ernst Dating: 10.12.1875