BRIEF [O.A.] Zepler, G... Author: Zepler, G... Recipient: Haeckel, Ernst Corporation: Der Weg - Freiheitl. Zeitschrift f. Politik u. Kultur Dating: 06.05.1918
POSTKARTE Stanezewski, Johann Author: Stanezewski, Johann Recipient: Haeckel, Ernst Dating: 27.05.1912
BRIEF OHNE UMSCHLAG Sokolowsky, Alexander Author: Sokolowsky, Alexander Recipient: Haeckel, Ernst Dating: 09.12.1901