Xu, K.; Agatha, S. & Dolan, J. (2021). World Ciliophora Database.
Ptychocylis ostenfeldi Kofoid & Campbell, 1929. Accessed through: RAS (Eds.) (2021) Register of Antarctic Species at: http://ras.biodiversity.aq/aphia.php?p=taxdetails&id=341670 on 2021-08-25
RAS (Eds.) (2021). Register of Antarctic Species.
Ptychocylis ostenfeldi Kofoid & Campbell, 1929. Accessed at: http://ras.biodiversity.aq/aphia.php?p=taxdetails&id=341670 on 2021-08-25