BRIEF OHNE UMSCHLAG Packard, Alpheus Spring Author: Packard, Alpheus Spring Recipient: Haeckel, Ernst Corporation: Brown University Dating: 29.12.1901
BRIEF OHNE UMSCHLAG Dearborn, Frank A. Author: Dearborn, Frank A. Recipient: Haeckel, Ernst Dating: 29.04.1901
BRIEF OHNE UMSCHLAG Krause, Adelheid Author: Krause, Adelheid Recipient: Haeckel, Ernst Dating: 24.08.1901
BRIEF OHNE UMSCHLAG Finlayson, Arthur Author: Finlayson, Arthur Recipient: Haeckel, Ernst Dating: 26.08.1901
BRIEF OHNE UMSCHLAG Tivadary, Kormos Author: Tivadary, Kormos Recipient: Haeckel, Ernst Dating: 30.12.1901