BRIEF [O.A.] Lébéda, I... Gr... Author: Lébéda, I... Gr... Recipient: Haeckel, Ernst Dating: 14.12.1913
BRIEF [O.A.] Siegmund, Heinrich Author: Siegmund, Heinrich Recipient: Haeckel, Ernst Dating: 20.02.1904
BRIEF [O.A.] Walter, Elisabeth Author: Walter, Elisabeth Recipient: Haeckel, Ernst Dating: 02.07.1892
BRIEF [O.A.] Gheorghiu, Ernest C... Author: Gheorghiu, Ernest C... Recipient: Haeckel, Ernst Corporation: Asezamintele Brancovenesti Dating: 16.02.1907
BRIEF [O.A.] Gheorghiu, Ernest C... Author: Gheorghiu, Ernest C... Recipient: Haeckel, Ernst Corporation: Asezamintele Brancovenesti Dating: 01.04.1907
BRIEF [O.A.] Gheorghiu, Ernest C... Author: Gheorghiu, Ernest C... Recipient: Haeckel, Ernst Corporation: Asezamintele Brancovenesti Dating: 17.05.1911