BRIEF [O.A.] Walther, Johannes Author: Walther, Johannes Recipient: Haeckel, Ernst Dating: 22.01.1886
BRIEF [O.A.] Walther, Johannes Author: Walther, Johannes Recipient: Haeckel, Ernst Dating: 24.01.1886
BRIEF [O.A.] Walther, Johannes Author: Walther, Johannes Recipient: Haeckel, Ernst Dating: 04.02.1886
BRIEF [O.A.] Walther, Johannes Author: Walther, Johannes Recipient: Haeckel, Ernst Dating: 21.02.1886
BRIEF [O.A.] Walther, Johannes Author: Walther, Johannes Recipient: Haeckel, Ernst Dating: 17.10.1886
BRIEF [O.A.] Schorer, Jacob Hendrik Author: Schorer, Jacob Hendrik Recipient: Haeckel, Ernst Corporation: Das Echo - Schorers Familienblatt Dating: 01.09.1886