Marshall, P. (1919). Fauna of the Hampden beds and classification of the Oamaru system. <em>Transactions of the New Zealand Institute.</em> 51: 226-250. page(s): 234, pl. 16, fig. 1 [details]
MolluscaBase eds. (2025). MolluscaBase. Trigonia densicostata P. Marshall, 1919 †. Accessed through: Marine Species Traits editorial board (2025) Marine Species Traits at: https://marinespecies.org/traits/aphia.php?p=taxdetails&id=1052220 on 2025-05-22
Marine Species Traits editorial board (2025). Marine Species Traits. Trigonia densicostata P. Marshall, 1919 †. Accessed at: https://www.marinespecies.org/traits/aphia.php?p=taxdetails&id=1052220 on 2025-05-22
original descriptionMarshall, P. (1919). Fauna of the Hampden beds and classification of the Oamaru system. <em>Transactions of the New Zealand Institute.</em> 51: 226-250. page(s): 234, pl. 16, fig. 1 [details]