BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Strasburger, Eduard Dating: 04.04.1878
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Strasburger, Eduard Dating: 24.05.1881
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Strasburger, Eduard Dating: 08.11.1882
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Strasburger, Eduard Dating: 06.09.1882
BRIEF MIT UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Strasburger, Eduard Dating: 07.03.1884
BRIEF MIT UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Strasburger, Eduard Dating: 28.02.1891
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Strasburger, Eduard Dating: 28.02.1894
BRIEF MIT UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Strasburger, Eduard Dating: 28.05.1894
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Strasburger, Eduard Dating: 01.12.1899