BRIEF [O.A.] Vatteroth, Wilh... Author: Vatteroth, Wilh... Recipient: Haeckel, Ernst Dating: 22.09.1908
BRIEF OHNE UMSCHLAG Krupp, Friedrich Alfred Author: Krupp, Friedrich Alfred Recipient: Haeckel, Ernst Dating: 12.05.1900
BRIEF OHNE UMSCHLAG Krupp, Friedrich Alfred Author: Krupp, Friedrich Alfred Recipient: Haeckel, Ernst Dating: 10.12.1901
BRIEF OHNE UMSCHLAG Krupp, Friedrich Alfred Author: Krupp, Friedrich Alfred Recipient: Haeckel, Ernst Dating: 21.04.1902
BRIEF OHNE UMSCHLAG Krupp, Friedrich Alfred Author: Krupp, Friedrich Alfred Recipient: Haeckel, Ernst Dating: 07.07.1902
BRIEF OHNE UMSCHLAG Krupp, Friedrich Alfred Author: Krupp, Friedrich Alfred Recipient: Haeckel, Ernst Dating: 22.09.1902
BRIEF [O.A.] Budde (et.al.) Author: Budde (et.al.) Recipient: Haeckel, Ernst Corporation: Friedrich Krupp Aktiengesellschaft Dating: 03.10.1903
BRIEF OHNE UMSCHLAG Krupp, Margarethe Author: Krupp, Margarethe Recipient: Haeckel, Ernst Dating: 01.07.1904