BRIEF [O.A.] Jägerskiold, L... A... Author: Jägerskiold, L... A... Recipient: Haeckel, Ernst Dating: 05.05.1902
BRIEF [O.A.] Jägerskiold, L... A... Author: Jägerskiold, L... A... Recipient: Haeckel, Ernst Dating: 01.08.1902
BRIEF [O.A.] Kögman, Ernst Author: Kögman, Ernst Recipient: Haeckel, Ernst Corporation: Idun Dating: 07.06.1919
BRIEF [O.A.] Chelius, Gustaf Author: Chelius, Gustaf Recipient: Haeckel, Ernst Corporation: Kammanditbolaget Chelius & Co., Bokförlag Dating: 06.03.1906