BRIEF [O.A.] Rottenburg, Paul von Author: Rottenburg, Paul von Recipient: Haeckel, Ernst Dating: 03.05.1902
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Charlotte Dating: 19.09.1876
BRIEF [O.A.] Rottenburg, Paul von Author: Rottenburg, Paul von Recipient: Haeckel, Ernst Dating: 28.07.1881
BRIEF OHNE UMSCHLAG Rottenburg, Paul von Author: Rottenburg, Paul von Recipient: Haeckel, Ernst Dating: 20.12.1892
BRIEF [O.A.] Findlay, John Wainman Author: Findlay, John Wainman Recipient: Haeckel, Ernst Dating: 23.09.1899
BRIEF [O.A.] Gemmill, James F... Author: Gemmill, James F... Recipient: Haeckel, Ernst Corporation: The University Dating: 22.01.1900
BRIEF OHNE UMSCHLAG Rottenburg, Paul von Author: Rottenburg, Paul von Recipient: Haeckel, Ernst Dating: 24.11.1901