BRIEF [O.A.] Foerster, Wilhelm Author: Foerster, Wilhelm Recipient: Haeckel, Ernst Dating: 15.05.1889
BRIEF [O.A.] Foerster, Wilhelm Author: Foerster, Wilhelm Recipient: Haeckel, Ernst Dating: 19.07.1893
TELEGRAMM Foerster, Wilhelm Author: Foerster, Wilhelm Recipient: Haeckel, Ernst Corporation: Sternwarte Dating: 16.02.1904
BRIEF OHNE UMSCHLAG Foerster, Wilhelm Author: Foerster, Wilhelm Recipient: Haeckel, Ernst Dating: 16.09.1913
BRIEF [O.A.] Foerster, Wilhelm Author: Foerster, Wilhelm Recipient: Haeckel, Ernst Corporation: Deutsch-Französische Liga, Deutsche Abteilung Dating: 18.10.1913
BRIEF MIT UMSCHLAG Foerster, Wilhelm Author: Foerster, Wilhelm Recipient: Haeckel, Ernst Dating: 08.08.1914
BRIEF OHNE UMSCHLAG Foerster, Wilhelm Author: Foerster, Wilhelm Recipient: Haeckel, Ernst Dating: 21.04.1893
BRIEF OHNE UMSCHLAG Foerster, Wilhelm Author: Foerster, Wilhelm Recipient: Haeckel, Ernst Dating: 29.12.1892
BRIEF OHNE UMSCHLAG Foerster, Wilhelm Author: Foerster, Wilhelm Recipient: Haeckel, Ernst Dating: 24.06.1893
BRIEF OHNE UMSCHLAG Foerster, Wilhelm Author: Foerster, Wilhelm Recipient: Haeckel, Ernst Dating: 05.05.1890