BRIEF OHNE UMSCHLAG Hertwig, Oscar Author: Hertwig, Oscar Recipient: Haeckel, Ernst Dating: 15.04.1879
BRIEF OHNE UMSCHLAG Hertwig, Richard Author: Hertwig, Richard Recipient: Haeckel, Ernst Dating: 11.03.1879
BRIEF [O.A.] Krauseneck, Heinrich Author: Krauseneck, Heinrich Recipient: Haeckel, Ernst Dating: 12.05.1879
BRIEF [O.A.] Krauseneck, Heinrich Author: Krauseneck, Heinrich Recipient: Haeckel, Ernst Dating: 19.12.1879
BRIEF [O.A.] Hofer, Carlo F... Author: Hofer, Carlo F... Recipient: Haeckel, Ernst Corporation: Carlo F. Hofer & Cia Dating: 24.03.1879
BRIEF OHNE UMSCHLAG Bukuwky, Jaromir Graf Author: Bukuwky, Jaromir Graf Recipient: Haeckel, Ernst Dating: 26.03.1879