BRIEF [O.A.] Graur, Georges St... Author: Graur, Georges St... Recipient: Haeckel, Ernst Dating: 07.06.1910
BRIEF [O.A.] Graur, Georges St... Author: Graur, Georges St... Recipient: Haeckel, Ernst Dating: 18.07.1910
BRIEF [O.A.] Graur, Georges St... Author: Graur, Georges St... Recipient: Haeckel, Ernst Dating: ??.??.1911
BRIEF [O.A.] Graur, Georges St... Author: Graur, Georges St... Recipient: Haeckel, Ernst Dating: 24.11.????
BRIEF [O.A.] Kanitz, August Author: Kanitz, August Recipient: Haeckel, Ernst Corporation: Bot. Garten