BRIEF [O.A.] Lewinsky, Bernhard Author: Lewinsky, Bernhard Recipient: Haeckel, Ernst Dating: 18.02.1912
BRIEF [O.A.] Lewinsky, Bernhard Author: Lewinsky, Bernhard Recipient: Haeckel, Ernst Dating: 15.02.1914
BRIEF OHNE UMSCHLAG Lewinsky, Bernhard Author: Lewinsky, Bernhard Recipient: Haeckel, Ernst Dating: 13.02.1909