Johns, M.J. & Barnes, C.R. & Orchard, M.J. (1997)
Taxonomy and biostratigraphy of Middle and Late Triassic elasmobranch ichthyoliths from north Eastern British Columbia. Geological Survey of Canada, Bulletin, 502, 1–235

Johns, M.J. & Barnes, C.R. & Orchard, M.J. (1997)
Taxonomy and biostratigraphy of Middle and Late Triassic elasmobranch ichthyoliths from north Eastern British Columbia. Geological Survey of Canada, Bulletin, 502, 1–235