BRIEF [O.A.] Wildhagen, Richard Author: Wildhagen, Richard Recipient: Haeckel, Ernst Dating: 17.03.1908
BRIEF OHNE UMSCHLAG Goßrau, Carl; Kilpper, Gustav Author: Goßrau, Carl; Kilpper, Gustav Recipient: Haeckel, Ernst Corporation: Deutsche Verlags-Anstalt Dating: 06.06.1908
POSTKARTE Engelsmann, Elisabeth Author: Engelsmann, Elisabeth Recipient: Haeckel, Ernst Dating: 25.02.1908
BRIEF [O.A.] Kaltenbach, Hedwig Author: Kaltenbach, Hedwig Recipient: Haeckel, Ernst Dating: 17.03.1908
BRIEF [O.A.] Lehmann, Fritz Author: Lehmann, Fritz Recipient: Haeckel, Ernst Corporation: Fritz Lehmann Verlag Dating: 07.03.1908
BRIEF [O.A.] Lehmann, Fritz Author: Lehmann, Fritz Recipient: Haeckel, Ernst Corporation: Fritz Lehmann Verlag Dating: 09.07.1908
BRIEF [O.A.] Lehmann, Fritz Author: Lehmann, Fritz Recipient: Haeckel, Ernst Corporation: Fritz Lehmann Verlag Dating: 13.11.1908