BRIEF [O.A.] Cogevina, Nicolaus Author: Cogevina, Nicolaus Recipient: Haeckel, Ernst Dating: 23.08.1877
BRIEF [O.A.] Cogevina, Nicolaus Author: Cogevina, Nicolaus Recipient: Haeckel, Ernst Dating: 17.09.1877
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Agnes Dating: 14.04.1877
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Charlotte Dating: 03.03.1877