BRIEF [O.A.] Blaise, T... T... Author: Blaise, T... T... Recipient: Haeckel, Ernst Corporation: Office of T. T. Blaise, M. D. Dating: 13.06.1898
BRIEF [O.A.] Knorr, Geo... W... Author: Knorr, Geo... W... Recipient: Haeckel, Ernst Corporation: Iowa Agricultural College Dating: 18.05.1884
BRIEF [O.A.] Knorr, Geo... W... Author: Knorr, Geo... W... Recipient: Haeckel, Ernst Dating: 21.12.1884