TELEGRAMM Hatschek, Berthold Author: Hatschek, Berthold Recipient: Haeckel, Ernst Corporation: Zoologisches Institut der Universität Dating: 06.03.1907
BRIEF [O.A.] Ivezic, Gerassim P... Author: Ivezic, Gerassim P... Recipient: Haeckel, Ernst Dating: 15.02.1907
BRIEF [O.A.] Ivezic, Gerassim P... Author: Ivezic, Gerassim P... Recipient: Haeckel, Ernst Dating: 31.12.1907
BRIEF [O.A.] Frisch Author: Frisch Recipient: Haeckel, Ernst Corporation: Der Floh Dating: 04.11.1907