BRIEF [O.A.] Wierzejski, Ludwig Author: Wierzejski, Ludwig Recipient: Haeckel, Ernst Dating: 09.07.1871
BRIEF [O.A.] Wierzejski, Ludwig Author: Wierzejski, Ludwig Recipient: Haeckel, Ernst Dating: 26.07.1871
BRIEF [O.A.] Schneider, Georg Heinrich Author: Schneider, Georg Heinrich Recipient: Haeckel, Ernst Dating: 08.10.1872
BRIEF [O.A.] Schneider, Georg Heinrich Author: Schneider, Georg Heinrich Recipient: Haeckel, Ernst Dating: 01.01.1873
BRIEF [O.A.] Schneider, Georg Heinrich Author: Schneider, Georg Heinrich Recipient: Haeckel, Ernst Dating: 04.06.1873
BRIEF [O.A.] Schneider, Georg Heinrich Author: Schneider, Georg Heinrich Recipient: Haeckel, Ernst Dating: 09.07.1873
BRIEF [O.A.] Schneider, Georg Heinrich Author: Schneider, Georg Heinrich Recipient: Haeckel, Ernst Dating: 15.08.1874
BRIEF [O.A.] Dybowski, Benedykt Author: Dybowski, Benedykt Recipient: Haeckel, Ernst Dating: 03.11.????