BRIEF [O.A.] Jacobsthal, Joh... Eduard Author: Jacobsthal, Joh... Eduard Recipient: Haeckel, Ernst Dating: 07.12.1897
BRIEF [O.A.] Jacobsthal, Joh... Eduard Author: Jacobsthal, Joh... Eduard Recipient: Haeckel, Ernst Dating: 19.12.1897
BRIEF [O.A.] Schultze, Leonhard Author: Schultze, Leonhard Recipient: Haeckel, Ernst Dating: 29.11.1897
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Senckenbergische Naturforschende Gesellschaft Dating: 01.06.1897