G. K. Gilbert. Systematic Asymmetry of Crest Lines in the High Sierras of California, ibid., pp. 579-588.
Emm. de Martonne. Sur la Formation des Cirques, Ann. de Géogr., vol. 10, 1901, pp. 10-16.
W. M. Davis. Glacial Erosion in North Wales, Quart. Jour. Geol. Soc. Lond., vol. 65, 1909, pp. 281-350, pl. 14.
Ed. Brückner. Die Glazialen Züge im Antlitz der Alpen, Naturw. Wochenschr., N. F., vol. 8, 1909.
William H. Hobbs. Characteristics of Existing Glaciers, pp. 1-96.
CHAPTER XXVII
SUCCESSIVE GLACIER TYPES OF A WANING GLACIATION