BRIEF [O.A.] Gottheiner, Friedrich Author: Gottheiner, Friedrich Recipient: Haeckel, Ernst Dating: 11.04.1905
BRIEF [O.A.] Schwarz, Arthur Author: Schwarz, Arthur Recipient: Haeckel, Ernst Corporation: Neue Photographische Gesellschaft AG Dating: 31.10.1903
BRIEF [O.A.] Brinkmann, E... Author: Brinkmann, E... Recipient: Haeckel, Ernst Corporation: Neue Photographische Gesellschaft AG Dating: 09.05.1904
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Neue Photographische Gesellschaft AG Dating: 13.11.1907
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Neue Photographische Gesellschaft AG Dating: 26.01.1909
