BRIEF [O.A.] Duplay, Geo... F... Author: Duplay, Geo... F... Recipient: Haeckel, Ernst Dating: 30.11.1904
BRIEF [O.A.] Duplay, Geo... F... Author: Duplay, Geo... F... Recipient: Haeckel, Ernst Dating: 28.12.1904
POSTKARTE Duplay, Geo... F... Author: Duplay, Geo... F... Recipient: Haeckel, Ernst Dating: 29.01.1905
POSTKARTE Duplay, Geo... F... Author: Duplay, Geo... F... Recipient: Haeckel, Ernst Dating: 20.03.1905
BRIEF [O.A.] Duplay, Geo... F... Author: Duplay, Geo... F... Recipient: Haeckel, Ernst Dating: 09.04.1905
POSTKARTE Duplay, Geo... F... Author: Duplay, Geo... F... Recipient: Haeckel, Ernst Dating: 18.04.1905