POSTKARTE Grazie, Marie Eugenie delle Author: Grazie, Marie Eugenie delle Recipient: Haeckel, Ernst Dating: 22.08.1903
POSTKARTE Recipient: Haeckel, Ernst Corporation: Pierer'sche Hofbuchdruckerei Stephan Geibel & Co. Dating: 18.04.1903
BRIEF [O.A.] Fromentin, A... Author: Fromentin, A... Recipient: Haeckel, Ernst Corporation: Université Populaire de Mante Dating: 01.07.1903