BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Charlotte Dating: 13.04.1873
BRIEF [O.A.] Schneider, G... H... Author: Schneider, G... H... Recipient: Haeckel, Ernst Dating: 26.11.1871
BRIEF [O.A.] Schneider, G... H... Author: Schneider, G... H... Recipient: Haeckel, Ernst Dating: 06.02.1872
BRIEF [O.A.] Schneider, G... H... Author: Schneider, G... H... Recipient: Haeckel, Ernst Dating: 26.03.1872
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