ANSICHTSKARTE Becker, Franz Johann Jakob Emil Author: Becker, Franz Johann Jakob Emil Recipient: Haeckel, Ernst Dating: 17.11.1907
BRIEF [O.A.] Baroja, Pio Author: Baroja, Pio Recipient: Haeckel, Ernst Corporation: Justicia Y Libertad, Comite Internacional Dating: 05.05.1910
BRIEF [O.A.] Casanova, Peregrín Author: Casanova, Peregrín Recipient: Haeckel, Ernst Dating: 20.03.1877
BRIEF [O.A.] Casanova, Peregrín Author: Casanova, Peregrín Recipient: Haeckel, Ernst Dating: 15.07.1877
BRIEF [O.A.] Casanova, Peregrín Author: Casanova, Peregrín Recipient: Haeckel, Ernst Dating: 12.12.1877
BRIEF [O.A.] Casanova, Peregrín Author: Casanova, Peregrín Recipient: Haeckel, Ernst Dating: 26.02.1878
BRIEF [O.A.] Casanova, Peregrín Author: Casanova, Peregrín Recipient: Haeckel, Ernst Dating: 24.01.1883
BRIEF [O.A.] Casanova, Peregrín Author: Casanova, Peregrín Recipient: Haeckel, Ernst Dating: 04.01.1876