BRIEF [O.A.] Stone, Mary Percival Author: Stone, Mary Percival Recipient: Haeckel, Ernst Dating: 03.02.1914
BRIEF OHNE UMSCHLAG Dearborn, Frank A. Author: Dearborn, Frank A. Recipient: Haeckel, Ernst Dating: 29.04.1901
BRIEF OHNE UMSCHLAG Ray-Kent, Helen Author: Ray-Kent, Helen Recipient: Haeckel, Ernst Dating: 23.07.1901
BRIEF [O.A.] Stone, Mary Percival Author: Stone, Mary Percival Recipient: Haeckel, Ernst Dating: 07.11.1916
BRIEF [O.A.] Dearborn, Frank A... Author: Dearborn, Frank A... Recipient: Haeckel, Ernst Dating: 18.01.1905
BRIEF [O.A.] Dearborn, Frank A... Author: Dearborn, Frank A... Recipient: Haeckel, Ernst Dating: 18.05.1905
BRIEF [O.A.] Dearborn, Frank A... Author: Dearborn, Frank A... Recipient: Haeckel, Ernst Dating: 20.12.1906
BRIEF [O.A.] Dearborn, Frank A... Author: Dearborn, Frank A... Recipient: Haeckel, Ernst Dating: 22.01.1907
BRIEF [O.A.] Burnham, Daniel A... Author: Burnham, Daniel A... Recipient: Haeckel, Ernst Dating: 02.02.1914