BRIEF OHNE UMSCHLAG Juliusburger, Otto Author: Juliusburger, Otto Recipient: Haeckel, Ernst Dating: 11.11.1908
BRIEF [O.A.] Juliusburger, Otto Author: Juliusburger, Otto Recipient: Haeckel, Ernst Dating: 25.12.1910
BRIEF [O.A.] Juliusburger, Otto Author: Juliusburger, Otto Recipient: Haeckel, Ernst Dating: 26.02.1911
BRIEF [O.A.] Juliusburger, Otto Author: Juliusburger, Otto Recipient: Haeckel, Ernst Dating: 24.01.1914
BRIEF [O.A.] Juliusburger, Otto Author: Juliusburger, Otto Recipient: Haeckel, Ernst Dating: 11.02.1914
BRIEF [O.A.] Juliusburger, Otto Author: Juliusburger, Otto Recipient: Haeckel, Ernst Dating: 27.02.1914
BRIEF [O.A.] Juliusburger, Otto Author: Juliusburger, Otto Recipient: Haeckel, Ernst Dating: 19.04.1914
BRIEF [O.A.] Juliusburger, Otto Author: Juliusburger, Otto Recipient: Haeckel, Ernst Dating: 21.06.1914