BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: N.N. Corporation: Zoologisches Institut der Universität Jena Dating: 22.04.1909
TODESANZEIGE Haeckel, Walter [et al.] Author: Haeckel, Walter [et al.] Recipient: N.N. Dating: 12.08.1919