BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Karl Dating: 14.09.1855
BRIEF OHNE UMSCHLAG Haeckel, Charlotte Author: Haeckel, Charlotte Recipient: Haeckel, Karl Dating: 28.04.1858
BRIEF OHNE UMSCHLAG Haeckel, Carl Gottlob Author: Haeckel, Carl Gottlob Recipient: Haeckel, Karl Dating: 20.05.1859
