BRIEF [O.A.] Schneider, G... H... Author: Schneider, G... H... Recipient: Haeckel, Ernst Dating: 01.01.1873
BRIEF [O.A.] Schneider, G... H... Author: Schneider, G... H... Recipient: Haeckel, Ernst Dating: 04.06.1873
BRIEF [O.A.] Schneider, G... H... Author: Schneider, G... H... Recipient: Haeckel, Ernst Dating: 09.07.1873