BRIEF [O.A.] Herzeele, A... von Author: Herzeele, A... von Recipient: Haeckel, Ernst Dating: 27.12.1875
BRIEF [O.A.] Herzeele, A... von Author: Herzeele, A... von Recipient: Haeckel, Ernst Dating: 15.06.1876
BRIEF [O.A.] Herzeele, A... von Author: Herzeele, A... von Recipient: Haeckel, Ernst Dating: 02.07.1876
BRIEF [O.A.] Herzeele, A... von Author: Herzeele, A... von Recipient: Haeckel, Ernst Dating: 16.04.1877
BRIEF [O.A.] Herzeele, A... von Author: Herzeele, A... von Recipient: Haeckel, Ernst Dating: 16.05.1877
BRIEF [O.A.] Herzeele, A... von Author: Herzeele, A... von Recipient: Haeckel, Ernst Dating: 09.06.1877