POSTKARTE Kertscher, Herbert R... Author: Kertscher, Herbert R... Recipient: Haeckel, Ernst Dating: 25.12.1913
BRIEF [O.A.] Kertscher, Herbert R... Author: Kertscher, Herbert R... Recipient: Haeckel, Ernst Corporation: Edda Verlag, Berlin Dating: 04.02.1914
BRIEF [O.A.] Kertscher, Herbert R... Author: Kertscher, Herbert R... Recipient: Haeckel, Ernst Corporation: Edda Verlag, Berlin Dating: 27.01.1915
POSTKARTE Cless, Alfred Martin Author: Cless, Alfred Martin Recipient: Haeckel, Ernst Dating: 17.10.1914