BRIEF [O.A.] Zacharias, Otto Author: Zacharias, Otto Recipient: Haeckel, Ernst Corporation: Bote aus dem Riesengebirge Dating: 13.10.1879
BRIEF [O.A.] Hentschel, Willibald Author: Hentschel, Willibald Recipient: Haeckel, Ernst Dating: 27.01.1879