ZIRKULARBRIEF Thomae, Johannes Author: Thomae, Johannes Recipient: Haeckel, Ernst et al. Corporation: Philosophische Fakultät der Universität Jena Dating: 04.12.1884
ZIRKULARBRIEF Haeckel, Ernst Author: Haeckel, Ernst Recipient: Snell, Karl; Schmid, Ernst Erhard [et al.] Dating: 01.02.1880
ZIRKULARBRIEF Haeckel, Ernst Author: Haeckel, Ernst Recipient: Schmidt, Adolf et al. Corporation: Philosophische Fakultät der Universität Jena Dating: 12.11.1871
BRIEF OHNE UMSCHLAG Claus, Rudolph Moritz Author: Claus, Rudolph Moritz Recipient: Haeckel, Ernst Dating: 02.03.1872
BRIEF OHNE UMSCHLAG Claus, Rudolph Moritz Author: Claus, Rudolph Moritz Recipient: Haeckel, Ernst Dating: 03.03.1872