BRIEF [O.A.] Beneden, Eduard van Author: Beneden, Eduard van Recipient: Haeckel, Ernst Dating: 11.07.1871
BRIEF [O.A.] Beneden, Eduard van Author: Beneden, Eduard van Recipient: Haeckel, Ernst Dating: 27.07.1871
BRIEF [O.A.] Beneden, Eduard van Author: Beneden, Eduard van Recipient: Haeckel, Ernst Dating: 08.09.1871