The zone of the dwindling river:—
E. Huntington. The Border Belts of the Tarim Basin, Bull. Am. Geogr. Soc., vol. 38, 1906, pp. 91-96; The Pulse of Asia, pp. 210-222, 262-279.
The war of dune and oasis:—
R. Pumpelly. Explorations in Turkestan, Expedition of 1904, etc., Pub. 73, Carneg. Inst., Washington, vol. 1, pp. 1-13.
E. Huntington. The Oasis of Kharga, Bull. Am. Geogr. Soc., vol. 42. 1910, pp. 641-661.
Th. H. Kearney. The Country of the Ant Men, Nat. Geogr. Mag., vol. 22, 1911, pp. 367-382.
Features of the arid lands:—
C. E. Dutton. Tertiary History of the Grand Cañon District, with Atlas, Mon. II, U. S. Geol. Surv., 1882, pp. 264, pls. 42, maps 23.
G. Sweinfurth. Map Sheets of the Eastern Egyptian Desert. Berlin, 1901-1902, 8 sheets.
The origin of the high plains:—