TELEGRAMM Breuer, Cornel H... Author: Breuer, Cornel H... Recipient: Haeckel, Ernst Dating: 16.02.1908
BRIEF [O.A.] Breuer, Cornel H... Author: Breuer, Cornel H... Recipient: Haeckel, Ernst Dating: 06.03.1908
BRIEF OHNE UMSCHLAG Horvath, Andreas Author: Horvath, Andreas Recipient: Haeckel, Ernst Dating: 01.10.1908