BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Julius Dating: 25.08.1909
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Julius Corporation: Zoologisches "Kloster" der Universität Jena Dating: 15.12.1909