BRIEF OHNE UMSCHLAG Hertwig, Oscar Author: Hertwig, Oscar Recipient: Haeckel, Ernst Dating: 29.07.1870
BRIEF OHNE UMSCHLAG Hertwig, Oscar Author: Hertwig, Oscar Recipient: Haeckel, Ernst Dating: 02.11.1870
BRIEF OHNE UMSCHLAG Hertwig, Richard Author: Hertwig, Richard Recipient: Haeckel, Ernst Dating: 02.09.1870