BRIEF [O.A.] Deregi, Oskar Author: Deregi, Oskar Recipient: Haeckel, Ernst Corporation: Nemzeti Szinház Dating: 11.09.1904
BRIEF [O.A.] Breuer, Cornel H... Author: Breuer, Cornel H... Recipient: Haeckel, Ernst Dating: 10.10.1904
BRIEF [O.A.] Breuer, Cornel H... Author: Breuer, Cornel H... Recipient: Haeckel, Ernst Dating: 16.10.1904