1. ^{{cite book|author=Justin Gerlach|title=Crustacea, Platyhelminthes, Nematoda, Nemertea, Annelida, Rotifera and Tardigrada of the Seychelles Islands|url=https://books.google.com/books?id=vodSxf1CziIC&pg=PA78|year=2011|publisher=Siri Scientific Press|isbn=978-0-9558636-9-1|pages=78–|quote=The class Heterotardigrada includes two orders: Arthrotardigrada and Echiniscoidea. The Arthrotardigrada includes only marine species, that very often have also a medial cirrus in the head; legs may be digitate or not. In non-digitate legs ...}}
2. ^{{Cite journal|last=Jørgensen|first=Aslak|last2=Faurby|first2=Søren|last3=Hansen|first3=Jesper G.|last4=Møbjerg|first4=Nadja|last5=Kristensen|first5=Reinhardt M.|date=2010-03-01|title=Molecular phylogeny of Arthrotardigrada (Tardigrada)|journal=Molecular Phylogenetics and Evolution|volume=54|issue=3|pages=1006–1015|doi=10.1016/j.ympev.2009.10.006|pmid=19822216}}
3. ^{{Cite work|last=Degma|first=Peter|last2=Bertolani|first2=Roberto |last3=Guidetti |first3=Roberto|date=30 June 2018|title=Actual checklist of Tardigrada species (2009-2018) |url=http://www.tardigrada.modena.unimo.it/miscellanea/Actual%20checklist%20of%20Tardigrada.pdf |publisher=University of Modena and Reggio Emilia |version=34th Ed.|access-date=25 November 2018 }}