BRIEF [O.A.] Ferguson, William Author: Ferguson, William Recipient: Haeckel, Ernst Dating: 09.03.1882
BRIEF [O.A.] Green, Staniforth Author: Green, Staniforth Recipient: Haeckel, Ernst Dating: 25.11.1881
ANSICHTSKARTE Escherich, Karl Leopold Author: Escherich, Karl Leopold Recipient: Haeckel, Ernst Dating: 13.02.1910