00266nam a22000977a 4500003000400000008004100004082001800045100001600063245004000079260004900119OSt231026b        |||||||| |||| 00| 0 eng d  aR551.48bG71H  aGray, D. M.  aH. B on the principles of hydrology  aKanpurIInformation centre Publicationc1970