BRIEF OHNE UMSCHLAG Becker, Daniel Georg Author: Becker, Daniel Georg Recipient: Haeckel, Ernst Dating: 28.01.1903
BRIEF OHNE UMSCHLAG Becker, Daniel Georg Author: Becker, Daniel Georg Recipient: Haeckel, Ernst Dating: 21.06.1903
BRIEF OHNE UMSCHLAG Bernstein, Herman Author: Bernstein, Herman Recipient: Haeckel, Ernst Corporation: The New-York Sun Dating: 16.06.1912