BRIEF OHNE UMSCHLAG Almeroth, Hans Author: Almeroth, Hans Recipient: Haeckel, Ernst Dating: 14.02.1914
BRIEF [O.A.] Bedot, M... Author: Bedot, M... Recipient: Haeckel, Ernst Corporation: Musée d'Histoire Naturelle de Genève Dating: 17.02.1914
BRIEF [O.A.] Baffrey, Alfred Author: Baffrey, Alfred Recipient: Haeckel, Ernst Corporation: Société Libre-Pensures Genève Dating: 16.02.1914