BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Karl Dating: 17.09.1890
BRIEF [O.A.] Cherno-Wyden, M... Author: Cherno-Wyden, M... Recipient: Haeckel, Ernst Dating: 30.08.1890
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Rottenburg, Paul von Dating: 03.09.1890