BRIEF [O.A.] Boner, Johann Heinrich Author: Boner, Johann Heinrich Recipient: Haeckel, Ernst Dating: 09.03.1874
BRIEF [O.A.] Boner, Johann Heinrich Author: Boner, Johann Heinrich Recipient: Haeckel, Ernst Dating: 01.06.1874
BRIEF [O.A.] Boner, Johann Heinrich Author: Boner, Johann Heinrich Recipient: Haeckel, Ernst Dating: 23.09.1874