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Strahler, A. N. (1957), "Quantitative analysis of watershed geomorphology". Transactions of the American Geophysical Union, 38, No. 6, 913–920.
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Strahler, A. N. (1957), "Quantitative analysis of watershed geomorphology". Transactions of the American Geophysical Union, 38, No. 6, 913–920.