POSTKARTE Bergstedt, J. A. Author: Bergstedt, J. A. Recipient: Haeckel, Ernst Corporation: Académie Royale Suédoise des Sciences Dating: 18.05.1909
BRIEF OHNE UMSCHLAG Ahlsell, Fritiof Author: Ahlsell, Fritiof Recipient: Haeckel, Ernst Dating: 23.02.1907
POSTKARTE Bergstedt, J... A... Author: Bergstedt, J... A... Recipient: Haeckel, Ernst Corporation: Académie Royale Suédoise des Sciences Dating: 01.07.1905
POSTKARTE Recipient: Haeckel, Ernst Corporation: Académie Royale Suédoise des Sciences Stockholm Dating: 18.05.1909
BRIEF [O.A.] Kögman, Ernst Author: Kögman, Ernst Recipient: Haeckel, Ernst Corporation: Idun Dating: 07.06.1919
BRIEF OHNE UMSCHLAG Retzius, Gustaf Author: Retzius, Gustaf Recipient: Haeckel, Ernst Dating: 19.11.1895