POSTKARTE Blochmann, Friedrich Author: Blochmann, Friedrich Recipient: Haeckel, Ernst Dating: 01.01.1893
POSTKARTE Blochmann, Friedrich Author: Blochmann, Friedrich Recipient: Haeckel, Ernst Dating: 05.11.1893
POSTKARTE Blochmann, Friedrich Author: Blochmann, Friedrich Recipient: Haeckel, Ernst Dating: 15.05.1903
BRIEF [O.A.] Blochmann, Friedrich Author: Blochmann, Friedrich Recipient: Haeckel, Ernst Corporation: Zoologisches Institut der Universität Dating: 14.02.1904
BRIEF [O.A.] Böhtlingk, Arthur Author: Böhtlingk, Arthur Recipient: Haeckel, Ernst Dating: 07.10.1891