BRIEF [O.A.] Luerssen, A... Author: Luerssen, A... Recipient: Haeckel, Ernst Corporation: Volksborngesellschaft Dating: 02.07.1915
BRIEF [O.A.] Erfurth, Hugo Author: Erfurth, Hugo Recipient: Haeckel, Ernst Corporation: Hugo Erfurth, Photographische Bildnisse Dating: 31.03.1915