BRIEF [O.A.] Davidoff, Alexander Author: Davidoff, Alexander Recipient: Haeckel, Ernst Dating: 01.11.1897
BRIEF [O.A.] Davidoff, Alexander Author: Davidoff, Alexander Recipient: Haeckel, Ernst Dating: 08.12.1897
BRIEF [O.A.] Renard, Karl von Author: Renard, Karl von Recipient: Haeckel, Ernst Corporation: Die Kaiserliche Naturforschende Gesellschaft in Moskau Dating: 12.02.1873
BRIEF OHNE UMSCHLAG Rottenburg, Paul von Author: Rottenburg, Paul von Recipient: Haeckel, Ernst Dating: 11.02.1911
BRIEF [O.A.] Saenger, N. Author: Saenger, N. Recipient: Haeckel, Ernst Corporation: Société Imperiale des Amis des Sciences naturelles Dating: 14.02.1874
BRIEF [O.A.] Renard, Karl von Author: Renard, Karl von Recipient: Haeckel, Ernst Corporation: Kaiserliche Gesellschaft der Naturforscher in Moskau Dating: 18.12.1871
BRIEF [O.A.] Renard, Karl von Author: Renard, Karl von Recipient: Haeckel, Ernst Corporation: Kaiserliche Gesellschaft der Naturforscher in Moskau Dating: 12.01.1872