Krenkel, E. (1915). Die Kelloway-Fauna von Popilani in Westrußland. <em>Palaeontographica.</em> 61: 191-362. page(s): 316, pl. 27, figs 18-21 [details]
MolluscaBase eds. (2024). MolluscaBase. Trigonia zonata var. grewingki Krenkel, 1915 †. Accessed through: Marine Species Traits editorial board (2024) Marine Species Traits at: https://www.marinespecies.org/traits./aphia.php?p=taxdetails&id=853590 on 2025-04-06
Marine Species Traits editorial board (2025). Marine Species Traits. Trigonia zonata var. grewingki Krenkel, 1915 †. Accessed at: https://www.marinespecies.org/traits/aphia.php?p=taxdetails&id=853590 on 2025-04-06
original descriptionKrenkel, E. (1915). Die Kelloway-Fauna von Popilani in Westrußland. <em>Palaeontographica.</em> 61: 191-362. page(s): 316, pl. 27, figs 18-21 [details]