KARTE Willkomm-Schneider, Martha Author: Willkomm-Schneider, Martha Recipient: Haeckel, Ernst Dating: 16.02.1914
BRIEF [O.A.] Willkomm-Schneider, Martha Author: Willkomm-Schneider, Martha Recipient: Haeckel, Ernst Dating: 22.02.1907
BRIEF [O.A.] Willkomm-Schneider, Martha Author: Willkomm-Schneider, Martha Recipient: Haeckel, Ernst Dating: 27.02.1919
POSTKARTE Willkomm-Schneider, Martha Author: Willkomm-Schneider, Martha Recipient: Haeckel, Ernst Dating: ??.02.????
POSTKARTE Willkomm-Schneider, Martha Author: Willkomm-Schneider, Martha Recipient: Haeckel, Ernst Dating: ??.02.1906
POSTKARTE Willkomm-Schneider, Martha Author: Willkomm-Schneider, Martha Recipient: Haeckel, Ernst Dating: 15.02.1919
TELEGRAMM Willkomm-Schneider, Martha Author: Willkomm-Schneider, Martha Recipient: Haeckel, Ernst Dating: 04.03.1???