BRIEF [O.A.] Schneider, G... H... Author: Schneider, G... H... Recipient: Haeckel, Ernst Dating: 15.05.1886
BRIEF [O.A.] Schneider, G... H... Author: Schneider, G... H... Recipient: Haeckel, Ernst Dating: 18.05.1886
BRIEF [O.A.] Schneider, G... H... Author: Schneider, G... H... Recipient: Haeckel, Ernst Dating: 19.05.1886
BRIEF [O.A.] Schneider, G... H... Author: Schneider, G... H... Recipient: Haeckel, Ernst Dating: 22.05.1886