BRIEF OHNE UMSCHLAG Günther, Wilhelm August Author: Günther, Wilhelm August Recipient: Haeckel, Ernst Dating: 29.03.1872
BRIEF OHNE UMSCHLAG Bleek, Theodor Author: Bleek, Theodor Recipient: Haeckel, Ernst Dating: 16.02.1902
BRIEF OHNE UMSCHLAG Bleek, Theodor Author: Bleek, Theodor Recipient: Haeckel, Ernst Dating: 06.11.1898