BRIEF OHNE UMSCHLAG Czapski, Siegfried Author: Czapski, Siegfried Recipient: Haeckel, Ernst Dating: 27.09.1906
BRIEF OHNE UMSCHLAG Chwolson, Orest Author: Chwolson, Orest Recipient: Schmidt, Heinrich Dating: 30.06.1906
BRIEF OHNE UMSCHLAG Bernelot Moens, Herman Marie Author: Bernelot Moens, Herman Marie Recipient: Haeckel, Ernst Dating: 13.07.1906
BRIEF OHNE UMSCHLAG Fischer, Gustav Author: Fischer, Gustav Recipient: Haeckel, Ernst Corporation: Gustav Fischer, Verlagsbuchhandlung Dating: 09.10.1906
BRIEF OHNE UMSCHLAG Engwer, Theodor; Kalkowski, Kurt Julius Author: Engwer, Theodor; Kalkowski, Kurt Julius Recipient: Haeckel, Ernst Dating: 12.02.1906
BRIEF OHNE UMSCHLAG Gompertz, Julius Author: Gompertz, Julius Recipient: Haeckel, Ernst Dating: 05.09.1906
BRIEF OHNE UMSCHLAG Grossmann, Otto Author: Grossmann, Otto Recipient: Haeckel, Ernst Dating: 01.07.1906