BRIEF OHNE UMSCHLAG Hein, Reinhold Author: Hein, Reinhold Recipient: Haeckel, Ernst Dating: 06.04.1863
BRIEF OHNE UMSCHLAG Hein, Reinhold Author: Hein, Reinhold Recipient: Haeckel, Ernst Dating: 02.04.1866
BRIEF OHNE UMSCHLAG Hein, Reinhold Author: Hein, Reinhold Recipient: Haeckel, Ernst Dating: 07.07.1867
BRIEF OHNE UMSCHLAG Hein, Reinhold Author: Hein, Reinhold Recipient: Haeckel, Ernst Dating: 23.02.1868
ANSICHTSKARTE Maurer, Friedrich Author: Maurer, Friedrich Recipient: Haeckel, Ernst Dating: 18.04.1915
BRIEF OHNE UMSCHLAG Kükenthal, Willy Author: Kükenthal, Willy Recipient: Haeckel, Ernst Dating: 01.09.1914
BRIEF OHNE UMSCHLAG Kükenthal, Willy Author: Kükenthal, Willy Recipient: Haeckel, Ernst Dating: 17.06.1918