BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Wundt, Wilhelm Dating: 23.05.1871
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Reimer, Georg Dating: 07.02.1871
BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Carl & Charlotte [Eltern] Dating: 25.01.1871
BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Carl & Charlotte [Eltern] Dating: 03.01.1871