BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Ullstein & Co. Verlagsbuchhandlung Dating: 14.11.1907
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Ullstein & Co. Verlagsbuchhandlung Dating: 13.07.1908
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Ullstein & Co. Verlagsbuchhandlung Dating: 08.08.1908
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Ullstein & Co. Verlagsbuchhandlung Dating: 20.10.1908
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Ullstein & Co. Verlagsbuchhandlung Dating: 13.07.1909
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Ullstein & Co. Verlagsbuchhandlung Dating: 10.03.1909
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Ullstein & Co. Verlagsbuchhandlung Dating: 20.03.1909
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Ullstein & Co. Verlagsbuchhandlung Dating: 08.11.1909
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Ullstein & Co. Verlagsbuchhandlung Dating: 16.11.1909
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Ullstein & Co. Verlagsbuchhandlung Dating: 11.06.1910
