BRIEF OHNE UMSCHLAG Krauseneck, Gustav Adolf Author: Krauseneck, Gustav Adolf Recipient: Haeckel, Ernst Dating: 20.12.1890
BRIEF OHNE UMSCHLAG Targioni Tozzetti, Author: Targioni Tozzetti, Recipient: Haeckel, Ernst Corporation: Gabinetto di Zoologia e Anatomia degli animali invertebrati Dating: 24.01.1890