BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Niess, Albert Dating: 28.06.1882
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Niess, Albert Dating: 20.12.1882
BRIEF OHNE UMSCHLAG Haeckel, Elisabeth Author: Haeckel, Elisabeth Recipient: Niess, Albert Dating: 29.12.1882