BRIEF [O.A.] Koch, Gottlieb von Author: Koch, Gottlieb von Recipient: Haeckel, Ernst Dating: 09.01.1876
BRIEF [O.A.] Koch, Gottlieb von Author: Koch, Gottlieb von Recipient: Haeckel, Ernst Dating: 23.02.1876
BRIEF [O.A.] Koch, Gottlieb von Author: Koch, Gottlieb von Recipient: Haeckel, Ernst Dating: 28.05.1876