BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Aristophot, Aktien-Gesellschaft Dating: 23.04.1904
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Aristophot, Aktien-Gesellschaft Dating: 28.12.1904
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Aristophot, Aktien-Gesellschaft Dating: 20.01.1905
BRIEF [O.A.] Stüber Author: Stüber Recipient: Haeckel, Ernst Corporation: Aristophot, Aktien-Gesellschaft Dating: 14.08.1905