BRIEF [O.A.] Jacobsthal, Joh... Eduard Author: Jacobsthal, Joh... Eduard Recipient: Haeckel, Ernst Dating: 03.04.1899
POSTKARTE Jacobsthal, Joh... Eduard Author: Jacobsthal, Joh... Eduard Recipient: Haeckel, Ernst Dating: 08.06.1899
BRIEF [O.A.] Jacobsthal, Joh... Eduard Author: Jacobsthal, Joh... Eduard Recipient: Haeckel, Ernst Dating: 03.11.1899
POSTKARTE Zachariewicz, Julian von Author: Zachariewicz, Julian von Recipient: Haeckel, Ernst Dating: 24.12.1909
BRIEF [O.A.] Zachariewicz, Julian von Author: Zachariewicz, Julian von Recipient: Haeckel, Ernst Dating: 05.11.1914
BRIEF [O.A.] Zachariewicz, Julian von Author: Zachariewicz, Julian von Recipient: Haeckel, Ernst Dating: 14.11.1914
BRIEF [O.A.] Zachariewicz, Julian von Author: Zachariewicz, Julian von Recipient: Haeckel, Ernst Dating: 11.12.1914
BRIEF [O.A.] Zachariewicz, Julian von Author: Zachariewicz, Julian von Recipient: Haeckel, Ernst Dating: 15.02.1915
BRIEF [O.A.] Zachariewicz, Julian von Author: Zachariewicz, Julian von Recipient: Haeckel, Ernst Dating: 06.04.1915