BRIEF [O.A.] Crisicopulo, Demetrio Author: Crisicopulo, Demetrio Recipient: Haeckel, Ernst Dating: 03.10.1881
BRIEF [O.A.] Syrski, Simeone Adamo de Author: Syrski, Simeone Adamo de Recipient: Haeckel, Ernst Dating: 19.07.1875
BRIEF [O.A.] Syrski, Simeone Adamo de Author: Syrski, Simeone Adamo de Recipient: Haeckel, Ernst Dating: 13.11.1874
BRIEF [O.A.] Syrski, Simeone Adamo de Author: Syrski, Simeone Adamo de Recipient: Haeckel, Ernst Dating: 12.02.1873