MolluscaBase eds. (2025). MolluscaBase. Opisthosiphon (Opisthosiphona) protractum C. de la Torre & J. B. Henderson, 1921. Accessed through: Marine Species Traits editorial board (2025) Marine Species Traits at: https://www.marinespecies.org/traits/aphia.php?p=taxdetails&id=1532265 on 2025-05-06
Marine Species Traits editorial board (2025). Marine Species Traits. Opisthosiphon (Opisthosiphona) protractum C. de la Torre & J. B. Henderson, 1921. Accessed at: https://www.marinespecies.org/traits/aphia.php?p=taxdetails&id=1532265 on 2025-05-06