Yehara, S. (1923). Cretaceous Trigoniae from southwest Japan. <em>Japanese Journal of Geology and Geography.</em> 2: 59-84. page(s): 78, pl. 9, figs 4, 5 [details]
MolluscaBase eds. (2025). MolluscaBase. Trigonia toyamai Yehara, 1923 †. Accessed through: Marine Species Traits editorial board (2025) Marine Species Traits at: https://www.marinespecies.org/traits/aphia.php?p=taxdetails&id=1474015 on 2025-05-18
Marine Species Traits editorial board (2025). Marine Species Traits. Trigonia toyamai Yehara, 1923 †. Accessed at: https://www.marinespecies.org/traits/aphia.php?p=taxdetails&id=1474015 on 2025-05-18
original descriptionYehara, S. (1923). Cretaceous Trigoniae from southwest Japan. <em>Japanese Journal of Geology and Geography.</em> 2: 59-84. page(s): 78, pl. 9, figs 4, 5 [details]