BRIEF OHNE UMSCHLAG Allmers, Hermann Author: Allmers, Hermann Recipient: Haeckel, Ernst Dating: 16.01.1886
BRIEF OHNE UMSCHLAG Allmers, Hermann Author: Allmers, Hermann Recipient: Haeckel, Ernst Dating: 13.02.1886
POSTKARTE Schulze, Franz Eilhard Author: Schulze, Franz Eilhard Recipient: Haeckel, Ernst Dating: 18.09.1886