BRIEF OHNE UMSCHLAG Keller, Conrad Author: Keller, Conrad Recipient: Haeckel, Ernst Dating: 19.07.1908
BRIEF OHNE UMSCHLAG Dodel-Müller, Luise Author: Dodel-Müller, Luise Recipient: Haeckel, Ernst Dating: 11.04.1908
BRIEF OHNE UMSCHLAG Schoeller, Caesar Author: Schoeller, Caesar Recipient: Haeckel, Ernst Dating: 26.01.1908
BRIEF OHNE UMSCHLAG Schoeller, Caesar Author: Schoeller, Caesar Recipient: Haeckel, Ernst Dating: 04.02.1908