PORTRÄTPOSTKARTE Friederici, Erna Author: Friederici, Erna Recipient: Haeckel, Ernst Dating: 24.08.1910
BRIEF OHNE UMSCHLAG Altmann-Bronn, Ida Author: Altmann-Bronn, Ida Recipient: Haeckel, Ernst Dating: 14.08.1910
BRIEF OHNE UMSCHLAG Bergdoldt, Wilhelm Author: Bergdoldt, Wilhelm Recipient: Haeckel, Ernst Dating: 21.09.1918
BILDPOSTKARTE Hinderdael, Irmgard van Author: Hinderdael, Irmgard van Recipient: Haeckel, Ernst Dating: 16.02.1914
BRIEF OHNE UMSCHLAG Greeff, Richard Author: Greeff, Richard Recipient: Haeckel, Ernst Dating: 27.08.1866
BRIEF OHNE UMSCHLAG Marchal, Edmond Author: Marchal, Edmond Recipient: Haeckel, Ernst Corporation: Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique Dating: 05.05.1904
TELEGRAMM Sethe-Seyberth, Louise; Sethe, Walter Author: Sethe-Seyberth, Louise; Sethe, Walter Recipient: Haeckel, Ernst Dating: 15.02.1914