BRIEF [O.A.] Steinmann, N.N. Author: Steinmann, N.N. Recipient: Haeckel, Ernst Corporation: Direction des Museums für Urgeschichte und Ethnographie Dating: 31.05.1886
BRIEF [O.A.] Dreyer, Friedrich Author: Dreyer, Friedrich Recipient: Haeckel, Ernst Dating: 14.02.1886
BRIEF [O.A.] Dreyer, Friedrich Author: Dreyer, Friedrich Recipient: Haeckel, Ernst Dating: 07.03.1886
BRIEF [O.A.] Dreyer, Friedrich Author: Dreyer, Friedrich Recipient: Haeckel, Ernst Dating: 14.03.1886
BRIEF [O.A.] Dreyer, Friedrich Author: Dreyer, Friedrich Recipient: Haeckel, Ernst Dating: 28.03.1886
BRIEF [O.A.] Dreyer, Friedrich Author: Dreyer, Friedrich Recipient: Haeckel, Ernst Dating: 25.04.1886
BRIEF [O.A.] Dreyer, Friedrich Author: Dreyer, Friedrich Recipient: Eggeling, Heinrich von Dating: 08.05.1886
