BRIEF OHNE UMSCHLAG Focke, Wilhelm Olbers Author: Focke, Wilhelm Olbers Recipient: Haeckel, Ernst Dating: 06.07.1865
BRIEF [O.A.] Focke, Gustav Waldemar Author: Focke, Gustav Waldemar Recipient: Haeckel, Ernst Dating: 14.11.1865
BRIEF [O.A.] Focke, Gustav Waldemar Author: Focke, Gustav Waldemar Recipient: Haeckel, Ernst Dating: 26.11.1865
BRIEF OHNE UMSCHLAG Brinckmann, Heinrich Author: Brinckmann, Heinrich Recipient: Haeckel, Ernst Dating: 10.11.1865
BRIEF OHNE UMSCHLAG Brinckmann, Heinrich Author: Brinckmann, Heinrich Recipient: Haeckel, Ernst Dating: 31.12.1865