BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Krauseneck, Heinrich Dating: 12.03.1877
BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Krauseneck, Heinrich Dating: 14.04.1877
BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Krauseneck, Heinrich Dating: 19.04.1877
BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Radowitz, Joseph Maria von Dating: 25.03.1887
BRIEF [O.A.] Ornstein, Bernhard Author: Ornstein, Bernhard Recipient: Haeckel, Ernst Dating: 26.11.1876
BRIEF [O.A.] Ornstein, Bernhard Author: Ornstein, Bernhard Recipient: Haeckel, Ernst Dating: 23.08.1879