[1] Changing ideas on the identity and stratigraphic significance of the Sheep Creek tephra beds in Alaska and the Yukon Territory, northwestern North America, 2008

Westgate, J.A., Preece, S.J., Froese, D.G., Pearce, N.J.G., Roberts, R.G., Demuro, M., Hart, W.K., and Perkins, W., 2008, Changing ideas on the identity and stratigraphic significance of the Sheep Creek tephra beds in Alaska and the Yukon Territory, northwestern North America: Quaternary International, v. 178, n. 1, p. 183-209, doi: 10.1016/j.quaint.2007.03.009.

[2] A catalogue of late Cenozoic tephra beds in the Klondike Goldfields and adjacent areas, Yukon Territory, 2011

Preece, S.J., Westgate, J.A., Froese, D.G., Pearce, N.J.G., and Perkins, W.T., 2011, A catalogue of late Cenozoic tephra beds in the Klondike Goldfields and adjacent areas, Yukon Territory: Canadian Journal of Earth Sciences, v. 48, p. 1386-1418, doi: 10.1139/e10-110