BRIEF [O.A.] Haltermann, Hermann Author: Haltermann, Hermann Recipient: Haeckel, Ernst Dating: 08.04.1869
BRIEF [O.A.] Haltermann, Hermann Author: Haltermann, Hermann Recipient: Haeckel, Ernst Dating: 08.05.1871
BRIEF [O.A.] Haltermann, Hermann Author: Haltermann, Hermann Recipient: Haeckel, Ernst Dating: 12.05.1871
BRIEF [O.A.] Lüdeking, H... Author: Lüdeking, H... Recipient: Haeckel, Ernst Corporation: Bremischer Lehrer-Verein Dating: 25.11.1907
BRIEF [O.A.] Luerssen, Christian Author: Luerssen, Christian Recipient: Haeckel, Ernst Dating: 22.10.1868
BRIEF [O.A.] Lipsius, Friedrich Author: Lipsius, Friedrich Recipient: Haeckel, Ernst Dating: 10.03.1909
