BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Karl Dating: 12.03.1890
BRIEF OHNE UMSCHLAG Wimpffen, Heinrich Emil von Author: Wimpffen, Heinrich Emil von Recipient: Haeckel, Ernst Corporation: Generalkonsulat Algier Dating: 14.04.1890
BRIEF [O.A.] Galli, Gottfried Author: Galli, Gottfried Recipient: Haeckel, Ernst Corporation: Kaiserlich Deutsches Consulat Dating: 19.02.1890