BRIEF [O.A.] Sangmineti, Alfred Geróme Author: Sangmineti, Alfred Geróme Recipient: Haeckel, Ernst Dating: 21.12.1904
BRIEF [O.A.] Korab, Waldemar C. de Author: Korab, Waldemar C. de Recipient: Haeckel, Ernst Dating: 19.06.1902