BRIEF [O.A.] Bibaud, J... J... E... Author: Bibaud, J... J... E... Recipient: Haeckel, Ernst Dating: 23.07.1911
BRIEF [O.A.] Bibaud, J... J... E... Author: Bibaud, J... J... E... Recipient: Haeckel, Ernst Dating: 14.09.1912
BRIEF [O.A.] Bibaud, J... J... E... Author: Bibaud, J... J... E... Recipient: Haeckel, Ernst Dating: 25.12.1914
BRIEF [O.A.] Macallum, A... B... Author: Macallum, A... B... Recipient: Haeckel, Ernst Corporation: British Association for the Advancement of Science Dating: 01.06.1897
BRIEF [O.A.] Moore, A... Bramlay Author: Moore, A... Bramlay Recipient: Haeckel, Ernst Corporation: The Northern Club Dating: 06.04.1914