BRIEF [O.A.] Nicotra, Leopoldo Author: Nicotra, Leopoldo Recipient: Haeckel, Ernst Dating: 30.05.1904
POSTKARTE Gonzenbach, Magdalena von Author: Gonzenbach, Magdalena von Recipient: Haeckel, Ernst Dating: 13.02.1904
POSTKARTE Santoro-Silipigni, Giovanni Author: Santoro-Silipigni, Giovanni Recipient: Haeckel, Ernst Dating: 20.02.1904