BRIEF [O.A.] Schultze, Leonhard Author: Schultze, Leonhard Recipient: Haeckel, Ernst Dating: 10.09.1908
BRIEF [O.A.] Thoms, G... Author: Thoms, G... Recipient: Haeckel, Ernst Corporation: Chemische Versuchs- und Samen-Control-Station am Polytechnikum Dating: 22.01.1882