| Reference no. | Description | year | Name used | Page |
|---|---|---|---|---|
| 833 | Ruppert, E.E., R.S. Fox and R.D. Barnes 2004 Invertebrate Zoology. A functional evolutionary approach. 7th Ed. Brooks/Cole, Thomson Learning learning, Inc. 990 p. | 2004 | Lingula unguis | --> |
| 85382 | Chou, L.M. and K.S. Tan 2008 Corals, worms, and molluscs: Cnidaria, Playhelminthes, Nemertea, Annelida, Brachiopoda, Mollusca. In pp. 39-61, Davison, G.W.H.; Ng, P.K.L.; Ho, H.C., 2008. The Singapore Red Data Book: Threatened plants and animals of Singapore. Singapore: The Nature Society, 285pp. | 2008 | Lingula unguis | --> |