Παραπομπή APA

Ward, R. C. (1967). Principles of hydrology. McGraw-Hill.

Παραπομπή Chicago Style

Ward, R C. Principles of Hydrology. Newyork: McGraw-Hill, 1967.

Παραπομπή MLA

Ward, R C. Principles of Hydrology. McGraw-Hill, 1967.