POSTKARTE Martens, Eduard von Author: Martens, Eduard von Recipient: Haeckel, Ernst Dating: 17.02.1879
BRIEF [O.A.] Martens, Eduard von Author: Martens, Eduard von Recipient: Haeckel, Ernst Corporation: Königl. Zoologisches Museum Dating: 25.01.1879
BRIEF [O.A.] Martens, Eduard von Author: Martens, Eduard von Recipient: Haeckel, Ernst Dating: 29.01.1879
BRIEF [O.A.] Martens, Eduard von Author: Martens, Eduard von Recipient: Haeckel, Ernst Dating: 25.12.1879
BRIEF [O.A.] Martens, Eduard von Author: Martens, Eduard von Recipient: Haeckel, Ernst Dating: 14.11.1887
BRIEF [O.A.] Martens, Eduard von Author: Martens, Eduard von Recipient: Haeckel, Ernst Dating: 16.08.1888
BRIEF OHNE UMSCHLAG Martens, Eduard von Author: Martens, Eduard von Recipient: Haeckel, Ernst Dating: 01.01.1856
BRIEF [O.A.] Martens, Eduard von Author: Martens, Eduard von Recipient: Haeckel, Ernst Dating: 26.12.1888
BRIEF [O.A.] Martens, Eduard von Author: Martens, Eduard von Recipient: Haeckel, Ernst Dating: 18.02.1889
BRIEF [O.A.] Martens, Eduard von Author: Martens, Eduard von Recipient: Haeckel, Ernst Dating: 02.11.1893