BRIEF [O.A.] Dieckmann, Gertha Author: Dieckmann, Gertha Recipient: Haeckel, Ernst Dating: 06.02.1913
BRIEF [O.A.] Dieckmann, Gertha Author: Dieckmann, Gertha Recipient: Haeckel, Ernst Dating: 17.02.1913
POSTKARTE Riedl, J... Author: Riedl, J... Recipient: Haeckel, Ernst Corporation: Weinproduktion "Achaia" Dating: 17.12.1913