POSTKARTE Finsterbusch, Ludwig Author: Finsterbusch, Ludwig Recipient: Haeckel, Ernst Dating: 02.01.1904
BRIEF OHNE UMSCHLAG Finsterbusch, Helene Author: Finsterbusch, Helene Recipient: Haeckel, Ernst Dating: 25.12.1904
POSTKARTE Finsterbusch, Ludwig Author: Finsterbusch, Ludwig Recipient: Haeckel, Ernst Dating: 30.12.1904
BRIEF OHNE UMSCHLAG Finsterbusch, Ludwig Author: Finsterbusch, Ludwig Recipient: Haeckel, Ernst Dating: 13.02.1904