BRIEF OHNE UMSCHLAG Radonetz, Eduard Author: Radonetz, Eduard Recipient: Haeckel, Ernst Dating: 23.08.1881
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Rodenberg, Julius Dating: 25.06.1881
BRIEF OHNE UMSCHLAG Bill, A. Author: Bill, A. Recipient: Haeckel, Ernst Corporation: Departement of the Interior, Washington D. C. Dating: 06.01.1881
