BRIEF [O.A.] Neumann, Carl W... Author: Neumann, Carl W... Recipient: Haeckel, Ernst Dating: 10.03.1919
BRIEF [O.A.] Neumann, Carl W... Author: Neumann, Carl W... Recipient: Haeckel, Ernst Dating: 09.02.1919
BRIEF [O.A.] Neumann, Carl W... Author: Neumann, Carl W... Recipient: Haeckel, Ernst Dating: 10.08.1919