BRIEF [O.A.] Kröner, Alfred Author: Kröner, Alfred Recipient: Haeckel, Ernst Corporation: Alfred Kröner Verlag Dating: 21.01.1916
BRIEF [O.A.] Kröner, Alfred Author: Kröner, Alfred Recipient: Haeckel, Ernst Corporation: Alfred Kröner Verlag Dating: 17.07.1916
BRIEF [O.A.] Kröner, Alfred Author: Kröner, Alfred Recipient: Haeckel, Ernst Corporation: Alfred Kröner Verlag Dating: 04.10.1916