BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Carl & Charlotte [Eltern] Dating: 17.03.1867
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: An die Freunde in Jena Dating: 18.03.1867
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: An die Freunde in Jena Dating: 19.03.1867