BRIEF [O.A.] Gorzawsky, Hubert Author: Gorzawsky, Hubert Recipient: Haeckel, Ernst Dating: 23.09.1907
BRIEF OHNE UMSCHLAG Buddenbrock, von Author: Buddenbrock, von Recipient: Haeckel, Ernst Dating: 20.09.1907
BRIEF OHNE UMSCHLAG Buchholz, G... Author: Buchholz, G... Recipient: Haeckel, Ernst Dating: 21.01.1907
POSTKARTE Bölsche, Wilhelm; Bölsche, Johanna Author: Bölsche, Wilhelm; Bölsche, Johanna Recipient: Haeckel, Ernst Dating: 08.09.1907
BRIEF OHNE UMSCHLAG Bergner, Franz Author: Bergner, Franz Recipient: Haeckel, Ernst Dating: 19.05.1907