BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Uslar-Gleichen, Bernhard von Dating: 04.09.1916
BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Uslar-Gleichen, Bernhard von Dating: 12.12.1916
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Heinrich Dating: 16.02.1916
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Heinrich Dating: 15.06.1916
BRIEF OHNE UMSCHLAG Groener, Maria Author: Groener, Maria Recipient: Haeckel, Ernst Dating: 06.01.1916