POSTKARTE Reinicke, Emanuel Author: Reinicke, Emanuel Recipient: Haeckel, Ernst Corporation: Wilhelm Engelmann Verlagsbuchhandlung Dating: 29.09.1896
POSTKARTE Harden, Maximilian Author: Harden, Maximilian Recipient: Haeckel, Ernst Corporation: Die Zukunft Dating: 28.03.1896
POSTKARTE Haferlandt, W. Author: Haferlandt, W. Recipient: Haeckel, Ernst Corporation: W. Haferlandt & Pippow, Anstalt für naturhistorische Lehrmaterialien Dating: 20.07.1896
POSTKARTE Rottenburg, Paul von Author: Rottenburg, Paul von Recipient: Haeckel, Ernst Dating: 02.05.1896