Levinsen, G.M.R. (1884 (for year 1883)). Systematisk-geografisk Oversigt over de nordiske Annulata, Gephyrea, Chaetognathi og Balanoglossi. Videnskabelige Meddelelser fra den naturhistoriske Forening i Kjöbenhavn. 45(1883): 95-354 + plates II-III.
World Polychaeta Database (WPolyDb) vol printed 1884 for year 1883, no article dates seen Note that the BHL digitisation is a separate from the journal with two paginations running. The true paginations matching the journal are the set near the spine. Ton van Haaren: On page 325 he ends his paper with Kopenhagen, in May 1884; also on BHL as: https://www.biodiversitylibrary.org/page/60030515 with pages 92-350