BRIEFABSCHRIFT Haeckel, Ernst Author: Haeckel, Ernst Recipient: Scheffauer, Herman Dating: 24.10.1912
BRIEFABSCHRIFT Haeckel, Ernst Author: Haeckel, Ernst Recipient: Scheffauer, Herman Dating: 19.09.1912
BRIEFABSCHRIFT Haeckel, Ernst Author: Haeckel, Ernst Recipient: Scheffauer, Herman Dating: 28.08.1912
BRIEFABSCHRIFT Gruyter, Walter de Author: Gruyter, Walter de Recipient: Haeckel, Ernst Dating: 25.04.1912
BRIEFABSCHRIFT Gruyter, Walter de Author: Gruyter, Walter de Recipient: Haeckel, Ernst Dating: 07.05.1912
BRIEFABSCHRIFT Gruyter, Walter de Author: Gruyter, Walter de Recipient: Haeckel, Ernst Dating: 30.05.1912