BRIEF [O.A.] Waldthausen, J... von [?] Author: Waldthausen, J... von [?] Recipient: Haeckel, Ernst Dating: 10.03.1907
BRIEF [O.A.] Waldthausen, J... von Author: Waldthausen, J... von Recipient: Haeckel, Ernst Corporation: Deutsche Gesandtschaft Dating: 11.03.1907
BILDPOSTKARTE Schuster, Adolf Niklaus Author: Schuster, Adolf Niklaus Recipient: Haeckel, Ernst Dating: 16.05.1909
POSTKARTE Schuster, Adolf Niklaus Author: Schuster, Adolf Niklaus Recipient: Haeckel, Ernst Dating: 11.03.1910
BRIEF [O.A.] Gonzalez, Clothilde M... Author: Gonzalez, Clothilde M... Recipient: Haeckel, Ernst Dating: 15.12.1901
BRIEF [O.A.] Schneiders, Carlos Author: Schneiders, Carlos Recipient: Haeckel, Ernst Dating: 15.04.1912
BRIEF [O.A.] Sangmineti, Alfred Geróme Author: Sangmineti, Alfred Geróme Recipient: Haeckel, Ernst Dating: 21.12.1904