WARD R. C., . (1967). Principles of Hydrology. London: McGraw-Hil Pub Co. Ltd, GB.
WARD R C, . 1967. Principles of Hydrology. London: McGraw-Hil Pub Co. Ltd, GB.
WARD R C, . Principles of Hydrology. London: McGraw-Hil Pub Co. Ltd, GB. 1967.