Lea, I. 1856. Description of a new species of Triquetra, Klein (Hyria, Lamarck). Proceedings of the Academy of Natural Sciences of Philadelphia 8: 79. Available electronically.
Lea, 1856. Proc. Acad. Nat. Sci. 8: 79.
Lea, 1857. Jour. Acad. Nat. Sci. 3 [O. 6]: 318 [38], pl. 32, fig. 32 [as ‘isocardioides’].
(renamed Plagiodon isocardioides Lea, 1857)
Lea, 1856. Proc. Acad. Nat. Sci. 8: 79.
(renamed Triquetra contorta Lea, 1857)