BRIEF OHNE UMSCHLAG Bölsche, Wilhelm Author: Bölsche, Wilhelm Recipient: Haeckel, Ernst Dating: 12.12.1912
BRIEF OHNE UMSCHLAG Bölsche, Wilhelm Author: Bölsche, Wilhelm Recipient: Haeckel, Ernst Dating: 21.02.1912
BRIEF OHNE UMSCHLAG Baege, Max Hermann Author: Baege, Max Hermann Recipient: Haeckel, Ernst Dating: 06.04.1912
BRIEF OHNE UMSCHLAG Baege, Max Hermann Author: Baege, Max Hermann Recipient: Haeckel, Ernst Dating: 19.04.1912