1. Keilhack, Conrad, , Ground-water and the hydrology of springs, Ger. Berlin, 1912,
2. Frisi, Paul, , , A treatise on rivers and torrents, . Trans. from the 2nd It. ed. by Maj.-Gen. John, Garstin, , of the Bengal Engineers; John Weale, , London, , 1860, .
3. Beardmore, Nathaniel, , Manual of hydrology, Waterlow and Sons, London, 1862,
4. Prinz, E., , Hydrology, Ger. 2 Julius Springer, Berlin, 1923,
5. General program of hydrology (Fr.);Imbeaux;Zs. Gewässerk.,1898