BRIEF [O.A.] Zubino, F... M... Author: Zubino, F... M... Recipient: Haeckel, Ernst Dating: 05.09.1873
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Acad. Verein der Naturhistoriker Dating: 21.02.1873
BRIEF [O.A.] Neumann-Spallart, Franz Xaver von Author: Neumann-Spallart, Franz Xaver von Recipient: Haeckel, Ernst Dating: 21.08.1873
BRIEF [O.A.] Neumann-Spallart, F... X... v. Author: Neumann-Spallart, F... X... v. Recipient: Haeckel, Ernst Dating: 28.05.1873