BRIEF [O.A.] Jacobsohn, J... H... Author: Jacobsohn, J... H... Recipient: Haeckel, Ernst Corporation: Papiergrosshandlung – Exporthaus Dating: 27.01.1914
POSTKARTE Witzleben, Else von Author: Witzleben, Else von Recipient: Haeckel, Ernst Dating: 10.05.1911
POSTKARTE Witzleben, Else von Author: Witzleben, Else von Recipient: Haeckel, Ernst Dating: 02.01.1913