Wolter, B.H.K.; Fonda, R.W. 2002. Gradient analysis of vegetation on the north wall of the Columbia River Gorge, Washington. Northwest Science. 76(1): 61-76.

Wolter, B.H.K.; Fonda, R.W. 2002. Gradient analysis of vegetation on the north wall of the Columbia River Gorge, Washington. Northwest Science. 76(1): 61-76.