BRIEF OHNE UMSCHLAG Friederici, Erna Author: Friederici, Erna Recipient: Haeckel, Ernst Dating: 23.12.1915
POSTKARTE Hilbert, August Author: Hilbert, August Recipient: Haeckel, Ernst Corporation: Verlagsbuchhandlung Georg Reimer in Berlin Dating: 30.10.1915
BRIEF OHNE UMSCHLAG Gruyter, Walter de Author: Gruyter, Walter de Recipient: Haeckel, Ernst Corporation: Verlagsbuchhandlung Georg Reimer in Berlin Dating: 22.07.1915
BRIEF OHNE UMSCHLAG Gruyter, Walter de Author: Gruyter, Walter de Recipient: Haeckel, Ernst Corporation: Verlagsbuchhandlung Georg Reimer in Berlin Dating: 18.11.1915
BRIEF OHNE UMSCHLAG Gruyter, Walter de Author: Gruyter, Walter de Recipient: Haeckel, Ernst Corporation: Verlagsbuchhandlung Georg Reimer in Berlin Dating: 29.10.1915
BRIEF OHNE UMSCHLAG Gruyter, Walter de Author: Gruyter, Walter de Recipient: Haeckel, Ernst Corporation: Verlagsbuchhandlung Georg Reimer in Berlin Dating: 18.10.1915
BRIEF OHNE UMSCHLAG Gruyter, Walter de Author: Gruyter, Walter de Recipient: Haeckel, Ernst Corporation: Verlagsbuchhandlung Georg Reimer in Berlin Dating: 26.10.1915
BRIEF OHNE UMSCHLAG Hilbert, August Author: Hilbert, August Recipient: Haeckel, Ernst Corporation: Verlagsbuchhandlung Georg Reimer in Berlin Dating: 01.12.1915
BRIEF OHNE UMSCHLAG Hilbert, August Author: Hilbert, August Recipient: Haeckel, Ernst Corporation: Verlagsbuchhandlung Georg Reimer in Berlin Dating: 26.11.1915
BRIEF OHNE UMSCHLAG Mead, Henry C. A. Author: Mead, Henry C. A. Recipient: Haeckel, Ernst Corporation: The Chicago Daily News, Berlin Bureau Dating: 20.01.1915