BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Rautenfeld, Paul von Dating: 25.02.1915
BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Rautenfeld, Paul von Dating: 11.03.1915
BRIEF MIT UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Rautenfeld, Paul von Dating: 13.05.1915
VISITENKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Rautenfeld, Paul von Dating: 11.03.1915