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
BRIEF [O.A.] Danielssen, D... C... Author: Danielssen, D... C... Recipient: Haeckel, Ernst Corporation: Bergens Museums Dating: 15.03.1886
BRIEF [O.A.] Desrousseaux, E... Author: Desrousseaux, E... Recipient: Haeckel, Ernst Dating: 21.10.1886