BRIEF [O.A.] Furnemont, Leo Author: Furnemont, Leo Recipient: Haeckel, Ernst Corporation: Fédération Internationale de la Libre Pensée Dating: 18.06.1904
BRIEF [O.A.] Furnemont, Leo Author: Furnemont, Leo Recipient: Haeckel, Ernst Corporation: Fédération Internationale de la Libre Pensée Dating: 03.08.1904
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Académie Royale des Sciences, des Lettres ...Bruxelles Dating: 26.02.1904
BRIEF OHNE UMSCHLAG Marchal, Edmond Author: Marchal, Edmond Recipient: Haeckel, Ernst Corporation: Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique Dating: 05.05.1904