World Register of Marine Species (WoRMS)
WoRMS (2026). Tunicata. Accessed at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=146420 on 2026-08-02
Balfour, F. M. (1881). A treatise on comparative embryology. London, MacMillan. Volume 2: i-xi, 1-655, i-xxi.