BRIEF OHNE UMSCHLAG Krabbe, Harald Author: Krabbe, Harald Recipient: Haeckel, Ernst Dating: 01.07.1869
BRIEF OHNE UMSCHLAG Krabbe, Harald Author: Krabbe, Harald Recipient: Haeckel, Ernst Dating: 03.07.1869
BRIEF OHNE UMSCHLAG Krabbe, Harald Author: Krabbe, Harald Recipient: Haeckel, Ernst Dating: 16.12.1869