BRIEF [O.A.] Knack, Carl August Author: Knack, Carl August Recipient: Haeckel, Ernst Dating: 04.04.1907
BRIEF [O.A.] Knack, Carl August Author: Knack, Carl August Recipient: Haeckel, Ernst Dating: 05.04.1908
BRIEF [O.A.] Oppenheim, Louise Author: Oppenheim, Louise Recipient: Haeckel, Ernst Dating: 12.07.1903
TELEGRAMM Roessler Author: Roessler Recipient: Haeckel, Ernst Corporation: Weimarer Kartell Dating: 09.03.1917
BRIEF [O.A.] Lautenschlager, Arnold Author: Lautenschlager, Arnold Recipient: Haeckel, Ernst Dating: 14.08.????