BRIEF [O.A.] Ziegler, Heinrich Ernst Author: Ziegler, Heinrich Ernst Recipient: Haeckel, Ernst Dating: 24.11.1900
BRIEF [O.A.] Theszóll, Charles Author: Theszóll, Charles Recipient: Haeckel, Ernst Dating: 23-02-1900
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Delle Grazie, Marie Eugenie Corporation: Zoologisches Institut der Universität Jena Dating: 14.01.1900
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Delle Grazie, Marie Eugenie Corporation: Zoologisches Institut der Universität Jena Dating: 28.08.1900
BRIEF [O.A.] Binet, René Author: Binet, René Recipient: Haeckel, Ernst Corporation: Ministère du Commerce, de l'Industrie, des Postes et des Télégraphes Dating: 13.03.1900