BRIEF [O.A.] Pascotini, B. Carl Author: Pascotini, B. Carl Recipient: Haeckel, Ernst Dating: 10.01.1873
BRIEF [O.A.] Syrski, Simeone Adamo de Author: Syrski, Simeone Adamo de Recipient: Haeckel, Ernst Dating: 12.02.1873
BRIEF [O.A.] Syrski, Simeone Adamo de Author: Syrski, Simeone Adamo de Recipient: Haeckel, Ernst Dating: 06.01.1873