Template:Amsden, 1983a
- Amsden, T.W. 1983. The Late Ordovician brachiopod genera Lepidocyclus and Hiscobeccus. In T.W. Amsden & W.C. Sweet, Upper Bromide Formation and Viola Group (Middle and Upper Ordovician) in eastern Oklahoma. Oklahoma Geological Survey Bulletin 132: 36–44. PDF