Nagaya, K., and E. Hirose. “Pattern of Stigma Numbers As a Taxonomic Character in Some Didemnid Ascidians (Aplousobranchia: Didemnidae)”. Zootaxa, vol. 3608, no. 1, Jan. 2013, pp. 87–93, doi:10.11646/zootaxa.3608.1.7.