BRIEF OHNE UMSCHLAG Zenker, Ernst Viktor Author: Zenker, Ernst Viktor Recipient: Haeckel, Ernst Dating: 26.04.1893
BRIEF OHNE UMSCHLAG Schulze, Franz Eilhard Author: Schulze, Franz Eilhard Recipient: Haeckel, Ernst Dating: 03.11.1893
BRIEF OHNE UMSCHLAG Schulze, Franz Eilhard Author: Schulze, Franz Eilhard Recipient: Haeckel, Ernst Dating: 15.11.1893
BRIEF [O.A.] Sutton, A... R... Author: Sutton, A... R... Recipient: Haeckel, Ernst Corporation: The Ernst Haeckel Club Dating: 26.06.1893