BRIEF OHNE UMSCHLAG Berninghaus, Walter Author: Berninghaus, Walter Recipient: Haeckel, Ernst Dating: 12.11.1907
BRIEF [O.A.] Bennett, Alexander Author: Bennett, Alexander Recipient: Haeckel, Ernst Dating: 04.02.1907
BRIEF OHNE UMSCHLAG Borngräber, Otto Author: Borngräber, Otto Recipient: Haeckel, Ernst Dating: ??.02.1907
BRIEF OHNE UMSCHLAG Becker, Daniel Georg Author: Becker, Daniel Georg Recipient: Haeckel, Ernst Dating: 11.02.1907
BRIEF OHNE UMSCHLAG Becker, Franz Johann Jakob Emil Author: Becker, Franz Johann Jakob Emil Recipient: Haeckel, Ernst Dating: 02.01.1907
BRIEF OHNE UMSCHLAG Becker, Franz Johann Jakob Emil Author: Becker, Franz Johann Jakob Emil Recipient: Haeckel, Ernst Dating: 14.02.1907