BRIEF OHNE UMSCHLAG Krabbe, Harald Author: Krabbe, Harald Recipient: Haeckel, Ernst Dating: 15.05.1907
BRIEF OHNE UMSCHLAG Krabbe, Harald Author: Krabbe, Harald Recipient: Haeckel, Ernst Dating: 28.06.1907
BRIEF OHNE UMSCHLAG Krabbe, Harald Author: Krabbe, Harald Recipient: Haeckel, Ernst Dating: 22.08.1907