BRIEF [O.A.] Hirth, Georg Author: Hirth, Georg Recipient: Haeckel, Ernst Corporation: Jugend Dating: 13.05.1898
BRIEF [O.A.] Hirth, Georg Author: Hirth, Georg Recipient: Haeckel, Ernst Corporation: Jugend Dating: 12.01.1903
BRIEF [O.A.] Hirth, Georg Author: Hirth, Georg Recipient: Haeckel, Ernst Corporation: Jugend Dating: 02.12.1903
BRIEF [O.A.] Hirth, Georg Author: Hirth, Georg Recipient: Haeckel, Ernst Corporation: Jugend Dating: 07.12.1903