BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Charlotte [Mutter] Dating: 15.05.1886
BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Charlotte [Mutter] Dating: 20.05.1886
BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Charlotte [Mutter] Dating: 28.05.1886
