OFFENER BRIEF Lagarrigue, Juan Enrique Author: Lagarrigue, Juan Enrique Recipient: Haeckel, Ernst Dating: 12.10.1903
BRIEF [O.A.] Duble Author: Duble Recipient: Haeckel, Ernst Corporation: Universidad Nacional Dating: 08.05.1904
POSTKARTE Mugado, Aurelis Nuney Author: Mugado, Aurelis Nuney Recipient: Haeckel, Ernst Dating: 26.02.1915
POSTKARTE Schuster, Adolf Niklaus Author: Schuster, Adolf Niklaus Recipient: Haeckel, Ernst Dating: 06.06.1909