BRIEF [O.A.] Cats, Martin W... Author: Cats, Martin W... Recipient: Haeckel, Ernst Dating: 04.02.1913
BRIEF [O.A.] Cats, Martin W... Author: Cats, Martin W... Recipient: Haeckel, Ernst Dating: 16.02.1913
BRIEF [O.A.] Cats, Martin W... Author: Cats, Martin W... Recipient: Haeckel, Ernst Dating: 27.02.1913
BRIEF [O.A.] Cats, Martin W... Author: Cats, Martin W... Recipient: Haeckel, Ernst Dating: 14.02.1914
BRIEF [O.A.] Cats, Martin W... Author: Cats, Martin W... Recipient: Haeckel, Ernst Dating: 28.02.1914