1. Soil-landscape relationships of a climax forest in the Allegheny high plateau Pennsylvania;Aquilar;Soil Sci. Soc. Am., J.,1985
2. The scenery of Pennsylvania, its origin and development;Ashley;Pennsylvania Geol. Surv., 4th Ser., Bull.,1933
3. Glacières or Freezing Caverns;Balch,1900
4. Morphology and stratigraphy of terraces in the upper Shenandoah Valley, Viriginia;Bell,1986
5. Periglacial studies in the United States;Black;Biuletyn Peryglacjalny,1964