[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] The Palisades is a key reference site for the middle Pleistocene of eastern Beringia: new evidence from paleomagnetics and regional tephrostratigraphy, 2013

Jensen, B.J.L., Reyes, A.V., Froese, D.G., and Stone, D.B., 2013, The Palisades is a key reference site for the middle Pleistocene of eastern Beringia: new evidence from paleomagnetics and regional tephrostratigraphy: Quaternary Science Reviews, v. 63, p. 91-108, http://dx.doi.org/10.1016/j.quascirev.2012.11.035