BRIEF OHNE UMSCHLAG Krabbe, Harald Author: Krabbe, Harald Recipient: Haeckel, Ernst Dating: 02.01.1872
BRIEF OHNE UMSCHLAG Krabbe, Harald Author: Krabbe, Harald Recipient: Haeckel, Ernst Dating: 24.01.1872
BRIEF [O.A.] Zülken, Chr... Author: Zülken, Chr... Recipient: Haeckel, Ernst Corporation: Universitetets Zoologiske Museum Dating: 23.05.1872