TELEGRAMM Sprenger, Gustav; Sprenger Therese Author: Sprenger, Gustav; Sprenger Therese Recipient: Haeckel, Ernst Dating: 16.02.1913
BRIEF [O.A.] Sprenger, Therese; Sprenger, Gustav Author: Sprenger, Therese; Sprenger, Gustav Recipient: Haeckel, Ernst Dating: 24.12.1913
BRIEF [O.A.] Sprenger, Therese Author: Sprenger, Therese Recipient: Haeckel, Ernst Dating: 22.03.1913
TELEGRAMM Dillmann Author: Dillmann Recipient: Haeckel, Ernst Corporation: Deutscher Monistenbund, Ortsgruppe Mainz Dating: 16.02.1913
BRIEFENTWURF Sprenger, Therese; Sprenger, Gustav Author: Sprenger, Therese; Sprenger, Gustav Recipient: Haeckel, Ernst Dating: 24.12.1913