BRIEF OHNE UMSCHLAG Sarasin, Fritz; Sarasin, Paul Author: Sarasin, Fritz; Sarasin, Paul Recipient: Haeckel, Ernst Dating: 13.04.1894
BRIEF OHNE UMSCHLAG Kükenthal, Willy Author: Kükenthal, Willy Recipient: Haeckel, Ernst Dating: 16.02.1894
BRIEF OHNE UMSCHLAG Kükenthal, Willy Author: Kükenthal, Willy Recipient: Haeckel, Ernst Dating: 11.07.1894